WARNING: Rob Wainwright said cafes and restaurants were very attractive terror targets

Rob Wainwright, the chief of the European Union's police agency Europol, said he was very concerned about the possibility of a militant attack during the footie competition.

The grave warning follows predictions that hell-bent ISIS, otherwise known as Daesh, will attack fan zones during the group stages.

The matches in France, between June 10 and July 10, could also be played behind closed doors in an emergency scenario.

A WORRY: Fans watch France play the 2006 World Cup final in a Paris bar

"It is shockingly easy to attack soft targets like cafes, restaurants or a concert hall," said Mr Wainwright.

"I am extremely concerned about the upcoming European soccer championship. It is an attractive target for terrorists."

France announced last month that it plans to extend the state of emergency in place since November's attacks on Paris by two months until after the championships.

Some 2.5 million spectators are expected for 51 matches involving 24 teams, 10 stadiums and nine cities.

At least 40,000 Brits are expected, but according to a survey of 1,600 UK fans by the Foreign Office, 57% are flocking to France without tickets.

And of those 57%, 51% plan to watch the action in fan zones and 13% will head to bars and pubs.

Mr Wainwright also said extra anti-terror security was being planned for the Euros well before the deaths of 130 in Paris and the ISIS suicide bombings in Brussels.

Speaking to German newspaper Die Welt, Mr Wainwright, as quoted today, added: "We need police units that can respond to attack scenarios and hostage situations like those seen in the Bataclan concert hall in Paris.

Security officials across the world are preparing for a "summer of fear" ahead of the Euros, the Rio Olympics and the Champions League final.