The man first threatened a group of soldiers who were out jogging at around 8 am (0600 GMT) in Varces-Allieres-et-Risset, near Grenoble, and later tried to run down another group of soldiers returning from a jog, army spokesman Colonel Benoit Brulon told AFP.

"The soldiers managed to get up onto the pavement without being hit," Brulon said.

The driver, whose motives were unknown, then sped off. Military sources later said a woman was also in the vehicle.

Prosecutors in Grenoble said the car had fake license plates, adding that it was not being treated as a terrorist attack for the moment.

Police sealed off the area and began a search for the driver and the woman, while the army stepped up security around the barracks, which houses members of the 27th mountain infantry brigade.

The incident comes with France on edge after a jihadist rampage in the southwest last week, where a 25-year-old radicalised gunman killed four people, including a policeman who took the place of a hostage in a supermarket siege.

On Thursday, the four victims of the attack in the medieval town of Carcassonne and nearby Trebes, including the heroic officer Arnaud Beltrame, will be laid to rest in the region.

The people of Trebes paid an emotional farewell to the three local victims at a ceremony in the square of the sleepy town on the Canal du Midi, held a day after a national tribute to Beltrame in Paris led by President Emmanuel Macron.

"You fell under the bullets of terrorism and took with you the insouciance of a little town in Occitanie where no one expected to ever experience such happenings," Trebes Mayor Eric Menassi told mourners at the gathering attended by Prime Minister Edouard Philippe.

- Security forces under fire -

The security forces have been targeted in several jihadist attacks that have claimed the lives of 240 people around France in the past three years.

At least six security force members have been killed during that period.

Radouane Lakdim, a Moroccan-born French national, fired at a group of policemen returning from a jog before storming the Super U store and shooting dead two people. He also shot dead the passenger of a car he hijacked in Carcassonne.

Beltrame intervened during the supermarket siege to take the place of a cashier Lakdim was using as a human shield.

But after three hours of negotiations the gunman, who claimed allegiance to the Islamic State group, slit Beltrame's throat before himself being shot dead by police.

Paying tribute to Beltrame at a national ceremony in Paris on Wednesday, President Emmanuel Macron said his act of self-sacrifice would "remain etched in French hearts".

Lakdim, who had a criminal record, was on a watchlist of suspected radicals, but authorities had concluded that he did not pose a threat.

His 18-year-old girlfriend, a radicalised Muslim convert, was charged with being part of a terrorist conspiracy.

Other attacks in which police officers have been killed include the massacre at the Charlie Hebdo satirical magazine in Paris in January 2015, in which two police officers were killed, and the fatal April 2017 shooting of a policeman on the Champs Elysees.

The army and police have also been targeted in several non-deadly attacks.

In August 2017, a man rammed his car into a group of soldiers on anti-terror patrol in the western Paris suburb of Levallois-Perret, injuring six people.

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