The Trump White House is reacting sceptically in private to North Korea's announcement of plans to freeze nuclear weapons testing, warning that dictator Kim Jong Un could be setting a trap and vowing not to back off a hardline stance ahead of a potential leaders' summit.

US President Donald Trump called Pyongyang's move "progress" and "good news" in a pair of tweets after the news broke on Saturday.

Behind the scenes, however, his aides cautioned today that Kim's statement that the North would halt testing and close one nuclear facility was more notable for what he left out: a direct pledge to work toward nuclear disarmament.

Although some foreign policy analysts were heartened that Kim appeared eager to set a positive tone for his summit with Trump, which could come in late May or early June, Trump aides were less enthused. In their view, Kim's moves aimed to offer relatively modest pledges - which could quickly be reversed - to create the "illusion" that he is "reasonable" and willing to compromise.


That, the Trump aides said, would make it more politically difficult for the United States to reject the North's demands.

Kim's announcement in Pyongyang surprised White House officials who had been anticipating him making some sort of statement to the North Korean people in advance of a summit with Trump but did not know when or how he would deliver it.

North Korea's state news agency read Kim's statement on television and issued a written version in English. The young dictator pledged to turn his regime's attention away from weapons development and toward boosting the economy on an "upward spiral."

White House aides viewed the statement as a signal that Kim's goal is to get the United States and its allies to ease the punishing economic sanctions that the Trump administration helped enact since the president took office. But they vowed that the Administration has learned from past mistakes in which North Korea violated agreements over its nuclear programme after sanctions were lifted.

Kim is set to meet with South Korean President Moon Jae In this week in what is being viewed as a preliminary summit ahead of the face-to-face with Trump. A date and location have not been announced for the latter summit.

South Korean officials said that Kim has signalled he is willing to discuss ways to formally end the Korean War, whose hostilities have been suspended since a 1953 armistice, and that he has dropped the North's long-standing demands that the United States withdraw tens of thousands of troops stationed on the peninsula.

A key test for Trump will be to navigate the competing pressures of the US allies in the region. Moon's liberal administration is attempting to broker a deal to reduce tensions over fears of war, while conservative Japanese Prime Minister Shinzo Abe, who views Kim's recent moves more suspiciously, is pressing Trump to ensure that Japan's interests are protected in any final agreement.

Abe used his two-day visit to Mar-a-Lago to emphasise that Japan will insist on "complete, verifiable and irreversible" steps toward denuclearisation. The Trump Administration also has taken a similar position, raising the question of whether anything that falls short of such an agreement at a summit would be a failure.


Some Washington-based analysts said that a more realistic path for Trump would be to tacitly acknowledge that the North, after relentlessly developing its arsenal for three decades, will not take immediate, concrete steps to eliminate the programme.

Another option, they suggested, would be to move first to enact constraints on the North's arsenal, such as capping the programme with limits to contain the threat. This would allow the North the security of maintaining some level of nuclear proficiency while enacting curbs on key bomb fuels and delivery systems. At the same time, the two countries would work toward establishing greater trust that could lead to more serious talks over full disarmament down the road.

"The reality is that North Korea has nuclear weapons, and we have to deal with that reality," said Toby Dalton, the co-director of the nuclear policy programme at the Carnegie Endowment for International Peace. In March, Dalton published an essay promoting a cap aimed at preventing the North from achieving "a fully-fledged, combat-ready arsenal."

"The gap between reality and what we're planning for is problematic," Dalton said, "as it creates expectations that can't be met in the summit process and we're back to where we were."

Seeking to put caps on the North's programme could be interpreted as the Trump Administration accepting North Korea as a nuclear state, a controversial idea inside the US Government, where a policy of nuclear nonproliferation has long been taken as an article of faith.

Senior US diplomats for Asia, including Susan Thornton, the acting assistant secretary of state, and Mark Lambert, the head of the Korea desk, are advocates of a policy that seeks full denuclearisation. But as reports circulated about a potential "bloody nose" military strike on North Korea last year, some US officials argued for containment as a short- or medium-term strategy aimed at preventing military action.

The idea of openly acknowledging North Korea as a nuclear power, however, remains an outlier position, especially given the assumption that it could trigger a nuclear arms race, prompting Japan and South Korea to pursue their own weapons.

Jon Wolfsthal, who oversaw arms control and nonproliferation policy at the National Security Council under President Barack Obama, said a major concern over accepting the North as a nuclear power, even for a limited period, is that Pyongyang would "pocket that and walk away. A lot of people are worried that's exactly what Kim is trying to do with the summit."

But Michael Auslin, an Asia scholar at the conservative Hoover Institution, said it is increasingly difficult for the United States to deny reality.

"We're seeing a de facto normalisation of North Korea's relationship with the world, as Kim Jong Un met with [Chinese President] Xi Jinping, plans to meet with Moon, and now Abe wants a meeting, and then Trump will meet him," Auslin said. "The reality is that everyone understands these discussions are about a programme that has made North Korea a nuclear power."