The US has warned that the Euro 2016 football championships being held in France next month could be a target of militant attacks, reports BBC News.
"The large number of tourists visiting Europe in the summer months will present greater targets for terrorists," the State Department said.
The event is being hosted from 10 June - 12 July at various venues.
France is already under a state of emergency following last year's Islamist-claimed attacks in Paris.
In its travel alert for US citizens, the State Department warns of the dangers of militant attacks throughout Europe.
The attacks could hit tourist sites, restaurants, commercial centres and transportation, it warns, with large events such as Euro 2016 singled out.