Given the task definition and input, reply with output. In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.

Media playback is unsupported on your device Media caption Theresa May said the decision was made by the Joint Terrorism Analysis Centre 
  
 The UK's terror threat level has been raised from "substantial" to "severe" in response to conflicts in Iraq and Syria, Home Secretary Theresa May says. 
  
 The new alert level rates the risk of an attack on the UK "highly likely", although Mrs May said there was no evidence to suggest one was "imminent". 
  
 It is the second highest of five possible UK threat levels. 
  
 David Cameron promised new legislation would make it easier to take passports from those travelling abroad to fight. 
  
 'Gaps in armoury' 
  
 The home secretary already has the power, under the Royal Prerogative, to withhold a passport if it is in the public interest to stop somebody travelling. 
  
 That power has been used 23 times between since April 2013 to stop people travelling abroad for alleged terrorist-related or criminal activity. 
  
 In a Downing Street press conference on Friday, the prime minister said Islamic State (IS) extremists - who are attempting to establish a "caliphate", or Islamic state - represented a "greater and deeper threat to our security than we have known before". 
  
 Media playback is unsupported on your device Media caption PM David Cameron: "We need to fill the gaps in our armoury" 
  
 He said that "learning lessons from the past doesn't mean there isn't a place for our military" in combating the threat, but did not commit to any military action. 
  
 He added the "threat is growing" from Britons travelling to fight with IS, saying at least 500 people had travelled from the UK "to fight in Syria and potentially Iraq". 
  
 Assistant Commissioner Mark Rowley, the Association of Chief Police Officers' lead for counter-terrorism, said security and protection measures were being increased following the raised threat level. 
  
 And efforts are continuing to identify a suspected British jihadist who appeared in IS footage of the killing of US journalist James Foley. 
  
 Image copyright PA 
  
 Analysis by Dominic Casciani, BBC home affairs correspondent 
  
 The raised threat level may not lead to visible signs of change on the streets - but it is a sign of the increased concern and security activity behind the scenes involving all of the UK's intelligence and security bodies. 
  
 The last time the level was this high was between January 2010 and the summer of 2011. This may have been linked to attempts by an al-Qaeda affiliate to smuggle bombs on to planes heading out of the Middle East. 
  
 The highest level is "critical"- meaning an attack is expected imminently. Officials have twice put the country on such an alert - in 2006 after the discovery of liquid bombs aimed at airliners and then the following year when extremists attempted to bomb Glasgow Airport (pictured) and London's West End. 
  
 In other words - if security chiefs had knowledge of a clear threat they could not contain, the level would already be one notch higher. 
  
 Mr Cameron said the murder of Mr Foley was "clear evidence - not that any more was needed - that this is not some far-off [problem], thousands of miles away, that we can ignore". 
  
 He did not give extensive details on what the changed threat level would mean, stressing people "should continue to go about our lives in the normal way". 
  
 Image copyright AP Image caption Islamic State has released images of its fighters after taking over Tabqa air base in Syria 
  
 Mr Cameron said other measures to tackle the threat included: 
  
 Emergency legislation to make communications data available to police and security services 
  
 Working with the Kurds to make sure they had the arms needed to battle IS militants 
  
 Assisting the US by providing intelligence gathering 
  
 Delivering aid supplies to communities displaced by IS 
  
 Changes in levels of policing in the UK, especially the numbers of armed police 
  
 More steps to deal with the threat would be announced on Monday, Mr Cameron said, which would include details on how to stop would-be terrorists travelling abroad. 
  
 He said there were "gaps in our armoury" which needed to be strengthened. 
  
 'Attacks against West' 
  
 Earlier, in a statement, Mrs May said: "The increase in the threat level is related to developments in Syria and Iraq where terrorist groups are planning attacks against the West. 
  
 "Some of those plots are likely to involve foreign fighters who have travelled there from the UK and Europe to take part in those conflicts. 
  
 "The first and most important duty of government is the protection of the British people." 
  
 Media playback is unsupported on your device Media caption Why has the terror level changed? 
  
 Mrs May said decisions about the threat level were made by the Joint Terrorism Analysis Centre (JTAC). 
  
 She added: "JTAC's judgements about that threat level are made on the basis of the very latest intelligence and are independent of ministers." 
  
 Increased patrols 
  
 AC Rowley said: "From this afternoon we will begin to increase our levels of visible patrols and implement other security and protection measures. 
  
 "We will also build on existing community relations to provide reassurance and seek their support and assistance in keeping the UK safe." 
  
 Media playback is unsupported on your device Media caption Pauline Neville-Jones, ex-chair of Joint Intelligence Committee: 'Threat level rise justified' 
  
 He urged communities and families to report anyone who is "vulnerable, a danger or escalating towards terrorism" by calling the anti-terrorist hotline on 0800 789 321. 
  
 Baroness Neville-Jones, a former chair of the Joint Intelligence Committee, said the higher threat level was "justified", adding it was "not something you do for the sake of it". 
  
 Shadow home secretary Yvette Cooper said the government's decision to remove control orders - to restrict the movements of terror suspects - should be reconsidered, adding there should be "proper powers in place when there is an extreme threat". 
  
 She said the government needed to support communities, and families in particular, and that more could be done through its anti-terrorism Prevent scheme. 
  
 The terror threat level was made public in 2006. 
  
 The level last changed in July 2011 when it was reduced to "substantial". 
  
 The threat level in the US has not changed. US secretary for homeland security Jeh Johnson said he had spoken to Mrs May about changes to the UK threat level but that he was not aware of any "specific, credible" threat to the US. 
  
 What is the Joint Terrorism Analysis Centre? ||||| British Prime Minister David Cameron vowed to confront radical Islam "at home and abroad" and the United Kingdom raised its terror level to "severe" in the wake of new revelations about Islamic State's butchery in Syria and Iraq. 
  
 Cameron, speaking from 10 Downing Street, said Britain's problem with homegrown radical jihadists joining the bloody battle engulfing the Middle East and threatening attacks on the west must be addressed with tough action. 
  
 "This is not some foreign conflict thousands of miles away that we can hope to ignore," the Conservative Party leader said. "The ambition to create an extremist caliphate in the heart of Iraq and Syria is a threat to our own security here in the UK. And that is in addition to the many other Al Qaeda-inspired terrorist groups that exist in that region. The first ISIL terrorist attacks on the continent of Europe have already taken place." 
  
 "We cannot appease this ideology," the Conservative Party leader said. "We have to confront it at home and abroad. To do this we need a tough, intelligent, patient, comprehensive approach to defeat the terrorist threat at its source. 
  
 "We cannot appease this ideology." More on this... UK raises terror threat level to 'severe' - British Prime Minister David Cameron 
  
 Cameron's words came one day after U.S. President Barack Obama said the U.S. is not contemplating imminent action against Islamic State in Syria. 
  
 "I don't want to put the cart before the horse. We don't have a strategy yet," Obama said Thursday. 
  
 International outrage at Islamic State continues to grow with daily reports and images of the terror group's savagery against Syrians, Iraqis and Kurds. On Thursday, video of Islamic State fighters marching more than 100 underwear-clad Syrian soldiers in the desert before summarily executing them appeared on the Internet. On Friday, Islamic State released photos of Kurdish Peshmerga soldiers captured ion Iraq, one of which was beheaded. 
  
 The UK government raised its terror threat level from "substantial" to "severe," the fourth highest of five levels, in response to events in Iraq and Syria. The move means a terrorist attack is highly likely, although there is no intelligence to suggest one is imminent, Home Secretary Theresa May said. Cameron noted it was the first time in three years the level was raised to severe by the U.K.'s Joint Terrorist Analysis Center. 
  
 "My first priority as Prime Minister is make sure we do everything possible to keep our people safe," Cameron said. 
  
 White House Press Secretary Josh Earnest said on Friday the U.S. has no current plant to raise its own threat level. 
  
 Earnest also went to great lengths Friday to say the U.S. is not "at war" with Islamic State and the Obama administration has been criticized for not addressing the issue of Islamic extremism explicitly and decisively enough, Cameron said the "root cause" of the terrorist threat in his nation is "Islamist extremism." hundreds and possibly more than 1,000 Britons have gone to Syria and Iraq to join Islamic State, which claims to have established a caliphate, or nation of strict Sharialaw, in Syria and Iraq. 
  
 Cameron said plans are being developed to stop British jihadists from traveling to Syria and Iraq and to make it easier to revoke their passports. He also said the nation will work to bar current fighters from returning from the Middle East. 
  
 Cameron distinguished between the religion of Islam and the "poisonous" political ideology of extremists. 
  
 “We are in the middle of a generational struggle between a poisonous and extremist ideology that I believe that we'll be fighting for years, and probably decades,” he said. |||||

David Cameron changed the UK threat level from "substantial" to "severe"—its second-highest level—and outlined measures the British government is taking to combat terrorism at a press conference today in London, reports the BBC. On the heels of the execution of James Foley and other disturbing ISIS activity in Iraq and Syria, the British government now believes an attack on the UK is "highly likely," though not necessarily "imminent" based on current evidence. The prime minister didn't mention any specific changes Brits should make to their daily routines, saying "we should continue to go about our lives in the normal way," but he did detail increased countermeasures the government would be taking, including helping Kurds secure weapons to fight off ISIS rebels, increasing humanitarian efforts to communities attacked by ISIS, and adding police at home. The UK has already been taking away passports of British citizens intent on fighting with ISIS, a legal deterrent it tapped into at least 14 times over the past year. "This is not some foreign conflict thousands of miles away that we can hope to ignore," he said, according to Fox News. "We need a tough, intelligent, patient, comprehensive approach to defeat the terrorist threat at its source."