The United States has urged its citizens abroad to “maintain a high level of vigilance” after the terrorist attacks in France.

Travellers have been told to take “appropriate steps to increase their security awareness” as many intelligence experts believe France’s allies could now be targeted.

Cedric Leighton, former U.S. intelligence officer: “They believe that an attack on one is actually an attack on all of the others. So for example, in the case of the French attacks, both the UK and the U.S. thought there would be the possibility of copycat attacks in those countries as well.”

The French embassy in Washington has become a focal point for people to pay their respects.

The US President was one of many to write words of support in a condolence book. He has also praised the country’s handling of the crisis.

Barack Obama, US President: “We’re hopeful that the immediate threat is now resolved, thanks to the courage and professionalism of the French personnel on the ground. The