WASHINGTON/JERUSALEM (Reuters) - The United States and Israel showed signs of seeking to defuse tensions on Sunday ahead of a speech in Washington by Israeli leader Benjamin Netanyahu when he will warn against a possible nuclear deal with Iran. 
 
 Policy differences over the negotiations with Iran remained firm, however, as Netanyahu set off for the United States to deliver the speech, which has imperiled ties between the two allies. 
 
 Israel fears that U.S. President Barack Obama’s Iran diplomacy, with an end-of-March deadline for a framework accord, will allow its arch foe to develop atomic weapons — something Tehran denies seeking. 
 
 By accepting an invitation from the Republican party to address Congress on Tuesday, the Israeli leader infuriated the Obama administration, which said it was not told of the speech before plans were made public in an apparent breach of protocol. 
 
 U.S. Secretary of State John Kerry reiterated Washington’s determination to pursue negotiations with Iran, saying on Sunday the United States deserved “the benefit of the doubt” to see if a nuclear deal could be reached. 
 
 Last week, Obama’s national security adviser, Susan Rice, said the partisanship caused by Netanyahu’s looming address was “destructive to the fabric of U.S.-Israeli ties”. 
 
 Asked about this on the ABC program “This Week”, Kerry said “the prime minister of Israel is welcome to speak in the United States, obviously. And we have a closer relationship with Israel right now in terms of security than at any time in history.” 
 
 He said he had talked to Netanyahu on Saturday, adding, “we don’t want to see this turned into some great political football.” Israel and the United States agreed that the main goal was to prevent Iran from getting a nuclear weapon, he said. 
 
 In remarks on Saturday at Jersualem’s Western Wall, Netanyahu said: “I would like to take this opportunity to say that I respect U.S. President Barack Obama.” He added that he believed in the strong bilateral ties and said, “that strength will prevail over differences of opinion, those in the past and those yet to come.” 
 
 Netanyahu did not repeat those remarks as he departed on Sunday. The Israeli prime minister, who is running for re-election in a March 17 ballot, has framed his visit as being above politics and he portrayed himself as being a guardian for all Jews. 
 
 “I’m going to Washington on a fateful, even historic, mission,” he said as he boarded his plane in Tel Aviv. “I feel that I am an emissary of all Israel’s citizens, even those who do not agree with me, and of the entire Jewish people,” he told reporters. 
 
 Netanyahu is expected to use his speech to urge Congress to approve new sanctions against Iran despite Obama’s pledge to veto such legislation because it would jeopardize nuclear talks. 
 
 U.S. officials fear he is seeking to sabotage the Iran diplomacy, and critics have suggested his visit is an elaborate election stunt that will play well with voters back home. 
 
 With Obama past the mid-point of his final term, his aides see an Iran nuclear deal as a potential signature achievement for a foreign policy legacy notably short on major successes. 
 
 While White House and Israeli officials insist that key areas of cooperation, from counter-terrorism to intelligence to cyber security, will remain unaffected, the divide over the Iran talks has shaped up as the worst in decades. 
 
 Previously Israel has always been careful to navigate between the Republican and Democratic camps. The planned address, however, has driven a rare wedge between Netanyahu’s government and some congressional Democrats. Some two dozen or more of them plan to boycott the speech, according to unofficial estimates. 
 
 IRANIAN ACCUSATION 
 
 Speaking in Tehran on Saturday, Iranian Foreign Minister Mohammad Javad Zarif accused Netanyahu of trying to undermine the nuclear talks in order to distract from the Palestinians’ unresolved bid for an independent state. 
 
 “Netanyahu is opposed to any sort of solution,” Zarif said. 
 
 Hard-line U.S. supporters of Israel say Netanyahu must take center-stage in Washington to sound the alarm over the potential Iran deal, even at the risk of offending long-time supporters. 
 
 But a U.S. official, speaking on condition of anonymity, said the “politicized” nature of his visit threatened “what undergirds the strength of the relationship”. 
 
 As one former U.S. official put it: “Sure, when Netanyahu calls the White House, Obama will answer. But how fast will he be about responding (to a crisis)?” 
 
 Israel's Prime Minister Benjamin Netanyahu listens as U.S. President Barack Obama (R) speaks, during their meeting in the Oval Office of the White House in Washington October 1, 2014. REUTERS/Kevin Lamarque 
 
 Last month, U.S. officials accused the Israeli government of leaking information to the Israeli media to undermine the Iran negotiations and said this would limit further sharing of sensitive details about the talks. 
 
 “What the prime minister is doing here is simply so egregious that it has a more lasting impact on that fundamental underlying relationship,” said Jeremy Ben-Ami, head of J Street, a liberal pro-Israel lobbying group aligned with Obama’s Iran policy. 
 
 Netanyahu will address the influential pro-Israel lobby AIPAC on Monday. Even as he makes his hard-line case against Iran, he is expected to try to keep tensions from spiraling, mindful that Israelis are wary of becoming estranged from their superpower ally. ||||| Photo Advertisement Continue reading the main story 
 
 WASHINGTON — President Obama and Prime Minister Benjamin Netanyahu of Israel offered radically divergent approaches to the perils of a nuclear-armed Iran on Monday even as they tried to cool down the personal nature of a long-distance dispute that has inflamed relations between the United States and Israel for more than a month. 
 
 
 
 
 
 
 
 
 
 On the eve of Mr. Netanyahu’s hotly debated address to Congress, the two leaders separately disclaimed personal animosity while laying out what amounts to the biggest policy schism between the two countries in years. Mr. Obama defended his diplomatic efforts to negotiate a deal with Iran while Mr. Netanyahu presented them as dangerously naïve. 
 
 “I have a moral obligation to speak up in the face of these dangers while there is still time to avert them,” Mr. Netanyahu told thousands of Israel supporters in Washington. “For 2,000 years, my people, the Jewish people, were stateless, defenseless, voiceless.” He added: “Today, we are no longer silent. Today, we have a voice. And tomorrow, as prime minister of the one and only Jewish state, I plan to use that voice” 
 
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 In an interview a few hours later, Mr. Obama said that he and Mr. Netanyahu had a “substantial disagreement” over how to prevent Iran from obtaining nuclear weapons. But he suggested that Mr. Netanyahu was an alarmist, saying that the Israeli leader had been unduly skeptical of a preliminary accord intended to slow the Iranian nuclear program during negotiations aimed at a longer-term resolution. 
 
 “Netanyahu made all sorts of claims — this was going to be a terrible deal, this was going to result in Iran getting $50 billion worth of relief, Iran would not abide by the agreement,” Mr. Obama told the Reuters news agency. “None of that has come true.” 
 
 Mr. Obama said that any deal would have to ensure that Iran was not capable of building a nuclear weapon in less than a year, and that the agreement must stand for at least 10 years. “If they do agree to it,” he said, “it would be far more effective in controlling their nuclear program than any military action we could take, any military action Israel could take, and far more effective than sanctions will be.” 
 
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 Mr. Netanyahu’s trip to Washington, coming just two weeks before Israeli elections and three weeks before a deadline in the Iran talks, has polarized politicians in both countries. The prime minister’s speech to a joint meeting of Congress on Tuesday — arranged by Speaker John A. Boehner without consulting the White House — immediately took on a partisan flavor, and Mr. Obama refused to meet with Mr. Netanyahu because his visit comes so close to the Israeli elections. 
 
 Vice President Joseph R. Biden Jr. and more than 50 Democratic lawmakers plan to skip Mr. Netanyahu’s speech. While the White House has not publicly encouraged a boycott, it sent an email late Monday inviting House Democratic aides to a trade meeting at the White House on Tuesday at a time that would make it hard for them to attend the speech. Advocates on both sides have published incendiary newspaper ads in recent days, including one attacking Susan E. Rice, the president’s national security adviser. 
 
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 The president expressed grievance about the speaking invitation, which the White House has interpreted as a way of bashing Mr. Obama and undercutting the Iran talks. In the Reuters interview, Mr. Obama said it would be as if Democrats in Congress invited the French president to speak after opposing President George W. Bush’s invasion of Iraq. “I guarantee you that some of the same commentators who are cheerleading now would have suggested that it was the wrong thing to do,” he said. 
 
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 But the president and his team also seemed intent on tamping down the intensity of the dispute. Secretary of State John Kerry, in Geneva for more talks with Iran, made a point of defending Israel before the United Nations Human Rights Council on Monday. And Mr. Obama sent Ms. Rice and Samantha Power, his ambassador to the United Nations, to address the American Israel Public Affairs Committee conference in Washington. 
 
 “This is not a personal issue,” Mr. Obama said. “I think that it is important for every country in its relationship with the United States to recognize that the U.S. has a process of making policy.” Even though Ms. Rice said last week that the issue could be “destructive” to bipartisan support of Israel, Mr. Obama said Monday that it was a distraction and would not be “permanently destructive.” 
 
 Mr. Netanyahu, appearing before an estimated 16,000 supporters of Israel at the Aipac conference, characterized the disagreement over Iran as a “family” fight that would ultimately be overcome, and he expressed gratitude to Mr. Obama for his support of Israel over the years. 
 
 “My speech is not intended to show any disrespect to President Obama or the esteemed office that he holds,” Mr. Netanyahu told the crowd, which greeted him with standing ovations. “I have great respect for both.” 
 
 He said he was sorry if anyone interpreted his visit as a political shot at Mr. Obama. “The last thing anyone who cares about Israel, the last thing that I would want, is for Israel to become a partisan issue,” he said, “and I regret that some people have misperceived my visit here this week as doing that. Israel has always been a bipartisan issue. Israel should always remain a bipartisan issue.” 
 
 But he emphasized that the threat of a nuclear-armed Iran looked different from Jerusalem than it does from Washington. “American leaders worry about the security of their country,” Mr. Netanyahu said. “Israeli leaders worry about the survival of their country.” 
 
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 Some supporters said they hoped Mr. Netanyahu’s measured language might defuse some of the anger of recent weeks. “I think he did well and lowered the temperature,” said Abraham H. Foxman, the national director of the Anti-Defamation League, who had called on Mr. Netanyahu to cancel the speech because of the fallout. “He could have pepped them up. He did not. It was an important message.” 
 
 Opponents of Mr. Netanyahu said he had done lasting harm. “I’m here to do damage control,” said Erel Margalit, a Labor member of Parliament who attended the Aipac conference. “I’m here to say we, too, are very concerned about Iran becoming a threshold nuclear state, but we’re interested in getting the discussions back to where they were.” 
 
 Republicans maintained that it was Mr. Obama who had done the damage by making a fuss over a speech rather than paying attention to the substance of Mr. Netanyahu’s message. “The address is an opportunity for you to hear from the leader of one of our closest allies about the grave threats we face from radical Islam and Iran,” Mr. Boehner’s office said in an email. 
 
 The tension of the moment was reflected at the Aipac conference before Ms. Power’s speech, when the audience was advised to “treat all our speakers as guests in our home.” Ms. Power and Ms. Rice both used their speeches to reaffirm Mr. Obama’s support for Israel and his determination to prevent Iran from obtaining nuclear weapons. 
 
 But Ms. Rice encountered skepticism when she laid out the argument for a possible deal, with the audience applauding the goal of barring Iran from nuclear enrichment altogether even as she called that unrealistic. “Sound bites won’t stop Iran from getting a nuclear weapon,” Ms. Rice said. “Strong diplomacy backed by pressure can.” ||||| Image copyright AFP Image caption Mr Netanyahu described Iran's nuclear programme as a great danger for Israel 
 
 US Secretary of State John Kerry has questioned the judgement of Israeli PM Benjamin Netanyahu over his stance on Iran's nuclear programme. 
 
 Mr Netanyahu has criticised the US and others for "giving up" on trying to stop Iran obtaining nuclear weapons. 
 
 The Israeli PM "may not be correct", Mr Kerry said after attending the latest Iran nuclear talks in Geneva. 
 
 Mr Netanyahu will address Congress next week, after an invitation by Republican leaders criticised by the White House. 
 
 Mr Kerry was reacting to a speech in which Mr Netanyahu had said the US and others were "accepting that Iran will gradually, within a few years, develop capabilities to produce material for many nuclear weapons". 
 
 "I respect the White House and the president of the United States but on such a fateful matter, that can determine whether or not we survive, I must do everything to prevent such a great danger for Israel," he said in a speech in Israel. 
 
 Image copyright AP Image caption Mr Kerry and his Iranian counterpart have been negotiating Iran's nuclear future 
 
 Having just concluded the latest round of nuclear talks with Iran in Geneva, Mr Kerry told senators President Obama had made it clear the policy was not to let Iran get nuclear weapons and Mr Netanyahu's might therefore not be correct. 
 
 The invitation for Mr Netanyahu to speak before Congress has angered Democrats. 
 
 A spokesman for the White House warned against reducing US-Israeli relations to a party-political issue. 
 
 Analysis - Barbara Plett Usher, BBC News, Washington 
 
 Administration officials have been hitting back at Mr Netanyahu's aggressive opposition to the nuclear deal they're negotiating with Iran - they're unhappy his speech to Congress will give him a platform to make his case as talks reach a critical juncture. 
 
 Susan Rice's comments highlight that strain and are the most direct reference by a senior official to the damage caused by the controversy over the visit. It was arranged by Republican congressional leaders without consulting the Democrats or the White House, just two weeks before Mr Netanyahu faces an election. 
 
 That has angered Democrats, some of whom feel they'll be forced to choose between President Obama and their desire not to upset Israel. More than a dozen have said they plan to skip the speech, opening an unprecedented breach in the usual show of bipartisan support for Israel. 
 
 Earlier, US National Security Adviser Susan Rice had gone further and said Mr Netanyahu's visit was "destructive to the fabric of the relationship". 
 
 Mr Netanyahu was invited by House Speaker John Boehner in what is seen as a rebuke to US President Barack Obama's Iran policy. 
 
 Mr Netanyahu is expected to discuss Iran, as well as Islamist militant groups, in his address. 
 
 The current tensions took root over a decade ago when Iran's nuclear programme first came to light. 
 
 Tough election 
 
 In 2005, Iran was referred to the UN Security Council, leading to a series of sanctions and UN resolutions requiring Tehran to stop enriching uranium. 
 
 The US and other powers - the so-called P5+1 - are negotiating with Iran on its nuclear programme. They want to agree a deal by March this year, but Mr Netanyahu is opposed to any agreement which might allow Tehran to retain the future capacity to build a nuclear weapon. 
 
 The Israeli leader has turned down an invitation to meet Senate Democrats privately, saying this "could compound the misperception of partisanship" surrounding his trip. 
 
 Media Analysis, BBC Monitoring 
 
 Israeli papers are divided over the Obama-Netanyahu spat, with one appearing bemused by the prime minister's stance. 
 
 "The odd, even tragic, thing is that Netanyahu has been doing all he can in recent weeks to help the Iranians achieve their goal," Hemi Shalev writes in Haaretz. 
 
 "First by alienating Obama and the administration, then by provoking the Democratic senators," he adds, referring to Mr Netanyahu's refusal to meet senate democrats separately. 
 
 A commentary in the pro-Netanyahu paper Yisrael Hayom comes out in strong support of the prime minister, saying his Congress speech will be "the last chance to prevent a bad agreement that leaves Iran a threshold nuclear state". 
 
 "The future will prove to what extent Israel was right to be at the forefront of the struggle against the US administration," Haim Shain writes. 
 
 In Yedioth Ahronoth, Guy Bechur dismisses fears of a deeper rupture between the US and Israel, and quotes a Gallop poll in the US as suggesting that 70% of Americans "support or very much support Israel". 
 
 Several Democratic members of Congress including Vice-President Joe Biden have said they will not attend the speech. 
 
 Republican leaders did not consult the Obama administration before inviting Mr Netanyahu, which the White House has called a breach of protocol. 
 
 White House spokesman Josh Earnest said on Wednesday: "The president has said the relationship between the US and Israel can't just be reduced to a relationship between the Republican party and the Likud party." 
 
 Mr Obama does not plan to meet Mr Netanyahu next week. The White House cited the "long-standing practice" of not meeting government leaders close to elections, which Israel will hold in mid-March. 
 
 Mr Netanyahu is fighting a tough election against the Labour Party's Yitzhak Herzog, who has focused on the prime minister's cooler relations with Mr Obama.
– Over the next two days, Washington will be a study in contrasts. Today, President Obama and two key advisers will push for a diplomatic means of avoiding a nuclear Iran; tomorrow, in a controversial speech to Congress, Israeli Prime Minister Benjamin Netanyahu will push back against the plan, the New York Times reports. To set the scene: Netanyahu left Tel Aviv yesterday for what he called "a fateful, even historic, mission" for which he is "an emissary of all Israel's citizens, even those who do not agree with me, and of the entire Jewish people," Reuters reports. His speech will likely call for boosted sanctions against Iran, but Obama has suggested he would veto any bill giving Congress a chance to legislate on the matter. This weekend, Netanyahu offered conciliatory words, saying he "respected" Obama and that "strength will prevail over differences of opinion." Obama will meet Reuters for an interview this afternoon, while National Security Adviser Susan Rice and UN Ambassador Samantha Power speak to the American Israel Public Affairs Committee, a group Netanyahu will also address, the Times reports. The paper sees the meetings as a chance for the administration to reaffirm its support for Israel. Indeed, John Kerry yesterday noted on ABC's This Week that Netanyahu "is welcome to speak in the United States, obviously. And we have a closer relationship with Israel right now in terms of security than at any time in history," Reuters reports. Kerry tomorrow will join international officials in Switzerland as they look to outline an Iranian deal by the month's end, the Washington Post reports. Kerry has been working closely—too closely, according to some Iranian lawmakers—with Iran's foreign minister to hammer out a deal, the Times reports. "He has made a huge investment of his time and energy in the talks, and his personal, hands-on involvement in recent months has been crucial to building momentum toward a deal," says an analyst. But some worry that Iran could read Kerry's "eagerness" as an opening to seek more concessions. Meanwhile, the UN's nuclear agency says Iran is coming up short on providing essential information, Reuters reports. "The (IAEA) is not in a position to provide credible assurance about the absence of undeclared nuclear material and activities in Iran, and therefore to conclude that all nuclear material in Iran is in peaceful activities," the agency's chief says.