U.K. sees terror threat as hundreds return from Syria

LONDON — More than 700 Britons are thought to have travelled to Syria and more than half have since returned home where they now pose a significant terrorism threat, British police said on Thursday.

Mark Rowley, the lead officer on counter-terrorism, also said there had been a record 338 arrests for terrorism-related offences last year, up by a third from 2013, with almost a half related to the conflict in Syria.

Rowley said of the 700 Britons who were believed to have gone, “a significant proportion” were thought to have tried to join Islamic State (IS) militants who have taken over swathes of Syria and Iraq.

About a half of those who had gone to the region were now thought to be back in Britain.

“(IS) and other terrorist groups are trying to direct attacks in the U.K.; encouraging British citizens to travel to Syria to fight and train; and are seeking, through propaganda, to provoke individuals in the U.K. to carry out violent attacks here,” Rowley said in a statement.

He said the threat ranged from “lone actors intent on carrying out crude and violent attacks” to more sophisticated and ambitious co-ordinated plots by organized networks. Of those arrested last year, 11% were women and 17% were aged under 20.

Among those Britons who have joined the conflict is Kuwaiti-born Londoner Mohammed Emwazi, dubbed “Jihadi John” by media, who has appeared in several Islamic State videos showing the beheading of Western hostages.