Hundreds of police are scouring eastern France to catch dead or alive a fugitive gunman thought to be behind a deadly shooting at the Christmas market in Strasbourg, which left three people dead and injured 13.

France raised its security threat to the highest level and deployed 1,800 additional soldiers to patrol streets and crowded areas across the country, while police issued a wanted poster for Chérif Chekatt with the warning: “Individual dangerous, above all do not intervene.”

Authorities said the 29-year-old was known to have developed radical religious views in jail and was known to the country’s security services as a potential security risk.

More than 700 police and soldiers are involved in the second day of the manhunt for Chekatt as they question his family members and set up checkpoints on the border with Germany.

Asked if police had been instructed to catch the suspect dead or alive, government spokesman Benjamin Griveaux told CNews: “It doesn’t matter. The best thing would be to find him as quickly as possible.”

It took four months for police to track down Salah Abdeslam, the prime surviving suspect from the November 2015 terror attack on Paris, who was found in an apartment in Brussels.

People walk past French Gendarmes who are standing guard in central Strasbourg two days after the deadly shooting (PATRICK HERTZOG/AFP/Getty Images)

Witnesses told investigators the suspect cried out “Allahu Akbar” (“God is Greatest”) as he opened fire on the Christmas market, a target Paris prosecutor Remy Heitz suggested may have been chosen for its religious symbolism.

He said the man attacked people at the market with a handgun and knife around 8pm on Tuesday and was shot in the arm during an exchange of gunfire with soldiers.

He then hijacked a taxi to another part of the city, boasting about the attack to the driver, and later exchanged more gunfire with police, before disappearing.

The wanted notice for Chérif Chekatt, which carries the warning: ‘Individual dangerous, above all do not intervene’ (Police Nationale via AP)

Chekatt’s police file photo shows a bearded man of North African descent, a prayer bruise blemishing the centre of his forehead. He has 27 criminal convictions for theft and violence, and has spent time in French, German and Swiss jails.

The attack came during a testing time for French president Emmanuel Macron, who announced tax concessions on Monday in an attempt to quell mass protests which have disrupted the country for a month and sparked the worst unrest in central Paris since the 1968 student riots.

Mr Griveaux said a decision had yet to be taken on whether to ban another planned “yellow vest” protest in Paris, which have seen cars torched, shops looted and the Arc de Triomphe defaced over the last three consecutive Sundays of riots in the capital.

“We’re simply saying at this stage that, given the events that are unfolding after the terrorist attack in Strasbourg, it would be preferable if everyone could go about a Saturday before the festive holidays in a quiet way,” Mr Griveaux said.

Fans at basketball arena sing French national anthem in tribute to Strasbourg shooting victims

The dead included a Thai tourist, 45-year-old Anupong Suebsamarn, according to the Thai Foreign Ministry and the website of the Khao Sod newspaper. It quoted his uncle as saying he and his wife had originally planned to visit Paris, but the protests there prompted them to change plans and go to Strasbourg instead.