TREBES, France (AP) — An armed man took hostages in a supermarket in southern France on Friday, killing three people and injuring about a dozen others before being shot to death when French police stormed the market, authorities said.

French President Emmanuel Macron said all evidence suggested that it was a terror attack — the first one since he became president in May.

It’s unclear how many victims there are overall, said Yves Lefebvre, secretary general of SGP Police-FO police union,

The attacker first fired six shots at police officers on their way back from jogging near the city of Carcassonne on Friday morning, said Lefebvre. The police were not in uniform but were wearing athletic clothes with police insignia. One police officer was shot in the shoulder, but the injury was not serious, Lefebvre said.

The suspect then went to a Super U supermarket in the nearby small town of Trebes, 60 miles (100 kilometers) southeast of Toulouse, taking an unknown number of people hostage.

In an hours-long standoff, special police units converged on the scene and authorities blocked roads and urged residents to stay away. Police then stormed the supermarket.

Interior Minister Gerard Collomb confirmed that the attacker had been shot dead and three other people were killed. Collomb went to Trebes after talking with Macron, who was at an EU summit in Brussels.

The Paris prosecutor’s office said counterterrorism investigators were taking over the probe but did not explain why. Unconfirmed media reports say the assailant claimed connections to the Islamic State group.

Collomb identified the suspect as Redouane Lakdim, 26, a petty criminal and small-time drug dealer who he said was radicalized and under police surveillance. Collomb said Lakdim in the standoff requested the release of the sole surviving assailant of Nov. 13, 2015, attacks in Paris that left 130 people dead.

France has been on high alert since a string of Islamic extremist attacks in 2015 and 2016 that killed more than 200 people. The shootings occurred in a normally quiet part of France, where the main tourist attraction is the treasured old city of Carcassonne, its medieval walls and its summertime festivals.

Macron said he will be back in Paris within hours. The attack poses a new challenge to his leadership as he also faces nationwide strikes and criticism of his reforms.

Standing next to Macron, German Chancellor Angela Merkel expressed her sympathy with those affected by the hostage-taking.

“When it comes to terrorist threats, we stand by France,” she said.

Corbet and Petrequin reported from Paris. Angela Charlton contributed to this report.