PARIS (Reuters) - Islamic State militants are gearing up for a campaign of bomb attacks on large crowds in France, host to next month’s Euro 2016 soccer championships, its spy chief has said.

French soldiers patrol in front of the Festival Palace before the opening of the 69th Cannes Film Festival in Cannes, France, May 11, 2016. REUTERS/Jean-Paul Pelissier

Rare remarks by Patrick Calvar, the head of France’s DGSI internal intelligence agency, to the parliament’s defense committee spelled out “a new form of attack ... characterized by placing explosive devices in places where there are large crowds and repeating this type of action to create a climate of maximum panic.

“Clearly, France is the most threatened and we know that Daesh (Islamic State) is planning new attacks,” Calvar told the committee on May 10, according to a transcript of his testimony released to the media on Thursday.

The comments came six months after militants killed 130 people in coordinated assaults on cafes, bars, a soccer stadium and a music hall across Paris.

He said the militant group had the numbers to launch the new attacks, including some 645 French citizens or residents currently in Syria or Iraq, of which 400 were fighters. A further 201 were either in transit to or from the region, he said.

Euro 2016 starts on June 10 and runs for a month at 10 stadiums across France. About 2.5 million spectators are expected for 51 soccer matches involving 24 teams. There will also be “fan zones” for crowds watching games on big screens in major cities.

France’s police force is stretched after two militant attacks last year and regular street protests.

However, the government say all measures are in place to ensure it runs smoothly.

“We will not drop our guard,” Prime Minister Manuel Valls told RTL radio on Thursday when asked about Calvar’s comments.

In a reminder of the challenges facing security forces, a fake bomb left behind after a training exercise at Manchester United’s stadium in Britain forced the evacuation of the 75,000-seater ground and the abandonment of a match last weekend.

Referring to the Arabic acronym for Islamic State, Calvar said Daesh was still using the same migrant routes through the Balkans to get its fighters into Europe.

However, with the group under pressure from U.S.-led air strikes in Syria it would want to hit back in Europe to show its supporters that it was still strong.

“It’s in a position where it would try to hit as quickly as possible and as hard as possible,” Calvar said.” It is facing military difficulties on the ground and so will want to divert attention and avenge coalition air strikes,” he said.