The UK has upgraded its travel advice for Europe amid terrorism fears after the US warned travellers to be vigilant in the region.

The Foreign and Commonwealth Office said there was a “high threat” of attacks in countries including France and Germany, rather than the “general threat” previously identified.

The changed travel advice follows intelligence indicating al Qaeda terrorists plan simultaneous Mumbai-style attacks in the UK, France and Germany.

The US State Department said: “Terrorists may elect to use a variety of means and weapons and target both official and private interests.

“US citizens are reminded of the potential for terrorists to attack public transportation systems and other tourist infrastructure.

“US citizens should take every precaution to be aware of their surroundings and to adopt appropriate safety measures to protect themselves when travelling.”

The updated FCO travel advice says “that like other large European countries, the French authorities continue to consider that there is a high threat of terrorism, and that like other large European countries, Germany has a high threat of terrorism”.

Responding to the US travel alert, home secretary Theresa May said the protection of Britons and visitors to the UK was the government’s “most important duty”.

She said: “As we have consistently made clear, we face a real and serious threat from terrorism. Our threat level remains at severe – meaning that an attack is highly likely.

“We work closely with our international partners in countering terrorism and the US advice is consistent with our assessment.”