Prime Minister David Cameron has said those militants pose the country’s greatest-ever security risk.

Britain on Friday warned its citizens travelling overseas of a heightened risk of attacks against them from militants linked to the Islamic State of Iraq and Syria (ISIS), updating its official travel advice to reflect an increase in the general threat level.

“There is considered to be a heightened threat of terrorist attack globally against UK interests and British nationals from groups or individuals motivated by the conflict in Iraq and Syria,” a statement from the Foreign Office said.

“You should be vigilant at this time.”

The warning will be included on all government travel advice web pages, and comes in response to an increase in the generalized threat level, rather than a specific credible threat, the statement said.

In August, Britain raised its national threat level to its second-highest rating, citing the risks posed by ISIS fighters returning from Iraq and Syria. Prime Minister David Cameron has said those militants pose the country’s greatest-ever security risk.

 
[wpResize]