LONDON — Britain has taken the unusual step of issuing a general terror warning to all U.K. travelers overseas because of fears that they could be targeted by Islamic State (ISIS) group terrorists seeking revenge for coalition actions in the Middle East.

The Foreign Office normally offers travel warnings for individual countries. The government, for example, already warns against travel to Syria, where the Islamic State group has seized territory.

But the Foreign Office updated travel advice pages Friday to reflect a generalized threat of terrorism globally.

"There is considered to be a heightened threat of terrorist attack globally against U.K. interests and British nationals from groups or individuals motivated by the conflict in Iraq and Syria," the Foreign Office said in a statement. "You should be vigilant at this time."