The US has warned its citizens that Europe is facing a “heightened risk of terror attacks” at Christmas markets and other seasonal holiday events.

The US State Department said it had “credible information” that Islamic State of Iraq and the Levant (Isil) and al-Qaeda were planning attacks and focusing on the “upcoming holiday season”.

It specifically warned American travellers to exercise caution at “holiday festivals, events and outdoor markets”.

The travel warning was issued as the US military said it expected Isil to resort to more traditional terrorist attacks after it loses its twin city strongholds of Mosul and Raqqa, both of which are under pressure.