Dozens of French police, including members of an elite tactical unit, on Thursday cordoned off a Strasbourg neighborhood where a suspected Christmas market gunman was last seen, according to reports.

One police official said security forces took action Thursday based on a “supposition only” that 29-year-old Cherif Chekkat could be hiding in a nearby building.

Meanwhile, authorities revised the death toll to three on Thursday after a person who had been kept alive while brain-dead succumbed to his injuries.

A fourth victim also has been declared brain-dead, according to Reuters.

More than 700 officers were involved in the manhunt for Chekatt, who has a long criminal record and had been flagged for extremism, government spokesman Benjamin Griveaux told CNews television.

The dragnet was aimed at catching the suspect “as soon as possible,” no matter whether he was dead or alive, and “put an end to the manhunt,” Griveaux said.

Armed French and German police manned controls on both sides of the Europe Bridge, which spans the frontier. Police in the German town of Kehl said they had received reports of possible sightings but all were false leads.

Authorities said a cabbie dropped Chekkat off Tuesday evening in the Neudorf neighborhood after the shooting, which also left 13 wounded.

Police distributed a photo of Chekatt, who was wounded in a gunfight with security forces, with the warning: “Individual dangerous, above all do not intervene.”

France raised its three-stage threat index to the highest level and deployed 1,800 additional soldiers across the country to help patrol streets and protect crowded events.

Griveaux also called on the “yellow vest” protesters demanding tax relief not to take to the streets.

The usually bustling streets of Strasbourg were eerily empty Thursday morning, with a heavy police and military presence, and the Christmas market remained closed, authorities said.

Neighbors in the housing complex where Chekatt’s family lived described the suspect as a typical young man.

“He was a little gangster, but I didn’t see any signs of him being radicalized,” a local association leader who declined to be named told Reuters outside Chekkat’s apartment building.

Some people lit candles and brought flowers to a makeshift memorial at the site of the attack.

“You can feel a very heavy atmosphere due all these events,” said resident Lucille Romance. “People are in a state of shock and are avoiding getting out of their house.”

The dead included a Thai tourist, 45-year-old Anupong Suebsamarn, according to the Thai Foreign Ministry.

Italian Interior Minister Matteo Salvini said one Italian — Europhonica radio consortium journalist Antonio Megalizzi, 28 — remained in critical condition.

French authorities said Chekatt, born in Strasbourg, had run-ins with the law starting at age 10 and his first conviction was at age 13.

He had been convicted 27 times, mostly in France but also in Switzerland and Germany, for crimes including armed robbery. He had been flagged for extremism and was on a watch list.

With Post wires