The US government is warning Americans travelling to France this summer that stadiums hosting matches in the Euro 16 soccer tournament as well as other affiliated venues likely to draw large numbers of fans could be vulnerable to becoming terrorist targets.

Concern about the potential for terror strikes aimed at the European Soccer Championships, which is set to run 10 June-10 July, was highlighted in a new, Europe-wide US travel advisory issued by the US State Department on Tuesday. It included venues where large numbers might gather to watch the games on jumbo screens, for instance in outdoor squares or parks, among the sites at risk.

“We are alerting US citizens to the risk of potential terrorist attacks throughout Europe, targeting major events, tourist sites, restaurants, commercial centres and transportation,” the advisory said. It stops short, however, of telling travellers to stay away from areas of potential risk but recommends they “exercise vigilance“, monitor local media and lay down plans to stay in touch with family in case of an emergency.

It also singled out the Catholic Church’s World Youth Day festival set for Krakow, Poland, for five days starting 25 July as an event likely to a trigger unusual levels of security vigilance and associated complications for travellers. The advisory will remain in effect until 31 August.

It noted that France, where the police resources have been stretched since the devastating Isis attacks in Paris last November that killed 130 people, also must contend with the staging of the annual Tour de France bicycling race during most of July.

Travel advisories are routinely issued but the State Department, in the same way the Foreign Office will on occasion issue travel warnings for Britons going overseas. It recently admonished US citizens to avoid travel under any circumstances to North Korea.

While the latest travel notice is labelled ‘Europe’ generally, it focuses in particular on Euro 16.

“France will host the European Soccer Championship from June 10-July 10,” it said. “Euro Cup stadiums, fan zones, and unaffiliated entertainment venues broadcasting the tournaments in France and across Europe represent potential targets for terrorists, as do other large-scale sporting events and public gathering places throughout Europe.

“France has extended its state of emergency through July 26 to cover the period of the soccer championship, as well as the Tour de France cycling race which will be held from July 2- 24.

The terror warning comes as French authorities are already bracing for a possible resurgence of hooliganism at some of the venues. Matches that have already been identified as having the potential for fan violence includes England v. Germany and Russia v. Wales.

With 24 teams competing, about 2.5 million fans, most from other countries, are expected to converge on France for the soccer tournament. The French government has conceded that the fear of fresh terror attacks, potentially by Isis, is a reality.

“We know that [Isis] is planning more attacks … and that France is clearly a target,” Patrick Calvar, head of the DGSI intelligence agency, told the French parliament's defence committee this month.