The suspected gunman in the deadly attack at a Christmas market in Strasbourg remains at large as counter terror police detained a fifth person in connection with the shooting.

French authorities said the latest man arrested was a member of the “entourage” of main suspect Chérif Chekatt, who is thought to have opened fire at the market on Tuesday, killing three people and injuring at least 11 others.

Forces had cordoned off an area in the Neudorf neighbourhood of Strasbourg on Thursday, where a taxi driver is believed to have dropped Chekatt off immediately after he escaped the scene of the shooting.

A police official said units, including the elite Raid squad, were acting on “supposition only” that the 29-year-old suspect could be hiding nearby.

Four members of Chekatt’s family, including his mother, father and two of his six brothers, had already been detained by police for questioning in connection with the attack.

Hundreds of officers have been mobilised to find the 29-year-old since Tuesday evening, after the gunman opened fire at the famous market while it was packed with visitors and tourists.

Government officials said focus remains on locating the suspect “as soon as possible,” while forces were prepared to take him “dead or alive” in order to bring the manhunt to an end.

Police named Chekatt as the shooting suspect on Wednesday, revealing he was already being monitored as a terror risk by French security authorities.

Chekatt, a Strasbourg native, was described by police as a “delinquent” with close to 30 prior convictions, who had served prison sentences not just in France, but also in Germany and Switzerland.

He is alleged to have yelled “God is great” in Arabic before opening fire from a security zone near the Christmas market.

Anupong Suebsamarn, a 45-year-old tourist who had been visiting from Thailand, is currently the only victim of the shooting to be named by authorities.

A Strasbourg resident in his 60s is also thought to have died in the attack, the city’s mayor Roland Ries told local media.

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Strasbourg remains in mourning, with candles lit and flowers left at the site of the attack. The Christmas market was closed again on Thursday.

On Wednesday evening, people prayed and sang in the nearby Protestant church Saint-Pierre-le-Jeune.

Pastor Philippe Eber said this is a moment “to think of those who died in this city because of violence. We also are thinking about all of those who weep for them, the families”.