American security agencies have found evidence that Isis terror cells in the UK and other European countries are plotting further attacks in the wake of the Brussels and Paris massacres.
James Clapper, the director of National Intelligence, said organised groups of militants were active in Germany, England and Italy.
“That is a concern of ours, obviously, and our European allies,” he said in response to a journalist’s question.
“We continue to see evidence of plotting on the part of Isil (Isis) in the countries you name.”
Speaking at an event in Washington DC organised by Christian Science Monitor, Mr Clapper said the US was doing all it can to share intelligence with European allies and “provoke more sharing” within the EU.
He said Isis cells embedded in Europe were “fanatics”, with a high level of security in operations, and were “to some extent” taking advantage of the refugee crisis.
“It’s something which the nations have a growing awareness of,” Mr Clapper added.
The intelligence director said another challenge was Isis militants’ increasingly sophisticated technological methods, which are allowing security agencies only to see a “snapshot” of plots.
“We don’t have the total picture all the time – if we did, then the plots would easily be thwarted,” Mr Clapper said, saying jihadists are aware of monitoring methods and attempt to evade them using encrypted applications.
He added: “The obstacles in Europe have somewhat to do with some of the fundamental conflict between, on the one hand, European Union 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 borders and its people. Those are sort of countervailing processes."
Mr Clapper also raised concerns about Isis’ claims of expansion in areas of Southeast Asia, including Bangladesh, where the group said its supporters hacked a university professor to death for “calling for atheism”.
The so-called Islamic State routinely boasts of its expansion through “wilayats” (provinces), which are normally local terrorist groups pledging allegiance to Abu Bakr al-Baghdadi.
Keith Vaz, chairman of the home affairs select committee, told The Daily Telegraph reports of an active Isis cell in England must be taken seriously.
"This is a worrying view which needs to be taken very seriously as it comes from a key ally that works with the UK closely on these matters," the Labour MP said.
"There are worrying concerns about free movement across the EU."
The Home Office has not yet responded to The Independent’s request for a comment.
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