Open borders across Europe have allowed Isil to plant sleeper cells across the continent and in the UK, poised to launch Paris or Brussels-style massacres, America’s intelligence chief has warned.
James Clapper, the US Director of National Intelligence, warned the free movement of citizens around the EU was “in conflict” with the need to protect security.
He warned some have taken advantage of the migrant crisis to slip in to Europe and called for better intelligence sharing between member states.
The comments came a week after the Daily Telegraph launched a campaign to highlight weaknesses in border security which saw senior policing and counter terrorism figures call for a review.
It also echoes warnings by the head of MI5 that Isil is intent on carrying out mass casualty attacks in the UK.
Mr Clapper, the principal intelligence adviser to the US President, warned Isil was spreading in Europe and that the Schengen agreement to allow free movement was costing the EU its security.
Briefing journalists in America, he said: “There’s a fundamental conflict – on the one hand there is the European Union’s incentives and drives to promote openness and free movement of people and goods and privacy, which is in some ways in conflict with the responsibility each country has as a nation state to protect the security of its border and its people.
“So there’s countervailing processes.”
James Clapper has warned Isil want to carry out Paris-style terror attacks in UK.
Mr Clapper also became the most senior Western official to publicly acknowledge the terror group’s extensive reach into the continent.
Asked whether the UK, Germany and Italy specifically had sleeper cells similar to the ones which carried out terror attacks in Brussels and Paris, he said: “Yes, they do.
“This is obviously a concern of ours and our European allies. We continue to see evidence of plotting on the part of Isil in the countries you name.”
Isil fanatics were behind the slaughter of 130 people in Paris in November and 32 people in a double suicide bombing in Brussels in March.
In the weeks and months since the attacks Mr Clapper said a rough portrait of the extremists’ presence in Europe had begun to emerge. It suggested the UK and Germany were particularly vulnerable to attack.
Mr Clapper said: “We’ve learned that they are fanatic, very OPSEC conscious — meaning operational security conscious — they’re very mindful of that.
“They have taken advantage, to some extent, of the migrant crisis in Europe — something which the nations, I think, have a growing awareness of.”
Keith Vaz, chairman of the Commons home affairs select committee, said: “This is a worrying view which needs to taken very seriously as it comes from a key ally which works with the UK closely on these matters.
“There are worrying concerns about free movement across the EU. Once someone passes through the external border of the EU there are simply no checks before they get to the UK. Even there they are not challenged robustly enough as they are EU citizens. These gaps need to be addressed.”
More than 800 people are believed to have left both countries to join Isil in Syria and Iraq and, as far as the UK is concerned, around half are believed to have returned.
Mohamed Abrini is a key suspect in Paris attacks and believed to be the ‘man in the hat’ bomber from Brussels attacks
One in five of those are considered a “high risk” and seven major plots have been thwarted in Britain in the last 18 months alone.
It has since emerged that one of the key suspects in both the Paris and Brussels attacks, Mohamed Abrini, had met contacts in the UK last summer.
Five people were arrested in Birmingham and at Gatwick earlier this month as part of wider investigations linked to Paris and Brussels.
In October, Andrew Parker, the Director General of MI5, said Isil was planning mass casualty attacks in Britain and that the threat from homegrown jihadists showed no sign of abating.
Mr Clapper also warned that better intelligence sharing was needed around Europe and that was “a major emphasis of ours”.He said the current level of threat was the highest he had seen in a career spanning 32 years.
His comments were echoed by President Barack Obama who on Monday rounded off visits to the UK and Germany.
“If we truly value our liberty, then we have to take the steps that are necessary to share information and intelligence within Europe, as well as between the United States and Europe, to stop terrorists from traveling and crossing borders and killing innocent people,” he said.