Hostage-taker killed at French supermarket

French police killed a gunman holed up in supermarket in southern France where he had taken hostages earlier on Friday, officials said.

Police union official Yves Lefebvre said police shot to death the suspected Daesh member involved in a hostage-taking situation, which was confirmed by Interior Minister Gerard Collomb.

A police source close to the investigation said the "hostage-taker is dead", adding that he was killed during a raid on the supermarket in which two officers were also wounded.

Earlier, three people were killed in three separate incidents which the French government is treating as acts of terrorism.

The armed man first hijacked a car in Carcassonne on Friday morning, killing a passenger and injuring the driver, the sources told AFP news agency on condition of anonymity.

He then shot at a group of policemen nearby, leaving one of the officers injured, before driving to the nearby town of Trebes, where he killed two people and injured another two at a Super U supermarket, the sources said.

The gunman taking hostages has asked for the release of November 2015 Paris attack suspect, Salah Abdeslam, BFMTV reported.

In Trebes, in a picturesque medieval town of around 5,000 people, the man "entered the Super U supermarket at around 11:15 am and shots were heard," AFP reported. 

"Most of the employees and customers of the Super U managed to flee," the source said, adding that a police officer was in contact with the gunman at the supermarket in the town of Trebes, near Carcassonne.

Hero policeman fighting for life 

A heroic policeman who swapped himself for a hostage was fighting for his life after he was shot by the hostage-taking gunman in the shooting spree that French President Emmanuel Macron branded "a terrorist attack".

Arnaud Beltrame, 45, was among a group of officers who rushed to the scene in the town of Trebes in southwest France Friday after the attacker stormed a supermarket and fired at shoppers and staff.

Beltrane offered to take the place of a woman the gunman had taken hostage and was shot and wounded before anti-terror police moved in to kill the attacker and end the siege.

Macron led tributes to the police officer, who has been hailed as a hero.

"He saved lives and honoured his colleagues and his country," he said.

"He is currently fighting for his life and all our thoughts go out to him and his family," he added.

High alert in France

If the link to Daesh is confirmed, the attack would be the first major incident since the election of centrist President Emmanuel Macron in May last year.

The shootings come with France still on high alert after a string of attacks since 2015, starting in January that year, with the assault on satirical magazine Charlie Hebdo that left 12 people dead.

France also suffered major attacks in Paris in November 2015 when Daesh militants killed 130 people at bars, restaurants, the Bataclan concert venue and the national stadium.

In July 2016, in another attack claimed by Daesh, a man drove a truck through revellers celebrating Bastille Day, killing 84 people.

A state of emergency was put in place just after the Paris attacks was finally lifted in October last year, but soldiers continue to patrol major tourist sites and transport hubs under an anti-terror mission.