Terror warnings on Euro football championship

"We know that Daesh [IS] in planning new attacks," he said, according to a transcript of the hearing published on Wednesday (18 May).

Calvar said IS would try to strike "as strongly and as rapidly as possible" in order to create a diversion from its difficult military situation in Syria and Iraq and as a retaliation against the international coalition's air strikes.

He said France could be faced with a "new kind of attack" and that the question was not "if" but "when and where" attacks would take place.

The risk is "a terror campaign characterised by leaving explosive devices in places where large crowds gather”, he said.

“This type of action would be multiplied to create a climate of panic," he said.

The intelligence chief gave no further details, but he spoke just a month ahead of the Euro 2016 tournament that will be held from 10 June to 10 July. Fifty-one matches will be played in 10 cities.

In an interview with Germany's Die Welt newspaper last weekend, Europol chief Rob Wainwright said Euro 2016 was "an attractive target for terrorists" and that he was looking at the event "with great concern".

The French sport minister said earlier this year that between seven and eight million people were expected to come to see the competition inside and outside the stadiums.

Security in and around the stadiums, especially in the so-called "fan zones" where people would watch the games on giant screens, have been a particular concern since the 13 November attacks in Paris.

The attacks started with the explosion of two suicide bombers outside the Stade de France, where 80,000 people were attending a match between France and Germany.

Ten thousand soldiers will be deployed during the competition as well as around 12,000 private security around fan zones. Exercises simulating attacks in stadiums have been organised, including one simulating a chemical attack.

'Crusader nations'

In addition to the crowds of supporters, another target could be the participating teams, according to a German criminal office (BKA) report leaked by German tabloid Bild.

"A successful attack on teams from 'crusader nations' including Germany would have a symbolic value," Bild quoted the report as saying, referring to teams from mainly Christian countries.

Twenty-four countries qualified for the competition. Among them only two, Albania and Turkey, have a population which is not mainly of Christian background.

According to Bild, the BKA report said France was a target because of "its colonial history in North Africa, its military involvement in Mali as well as its military support in the fight against IS in Iraq and Syria".