The United States is warning its citizens of the threat of terrorist attacks in Europe this summer, saying that targets could include the Euro 2016 football tournament in France.
The State Department issued the alert as French police reviewed security protocols at the Stade de France in Paris, a site already targeted by suicide bombers last November.
The stadium will host the opening match of the championships on June 10.
The US warning covers “major events, tourist sites, restaurants, commercial centers and transportation”.
It points to the Catholic Church’s World Youth Day event in Krakow, Poland, in July, saying that local infrastructure may be strained by the up to 2.5 million visitors set to attend.
The travel alert expires on August 31.
Concern about security in Europe has grown since November’s Paris attacks that claimed 130 lives as well as the suicide bombings in Brussels in March that killed 32 people.