PARIS, Dec. 12 (Xinhua) -- An armed man suspected of killing two people and wounding several others in the French city of Strasbourg on Tuesday evening did not cross the German border and was still at large in French territory, Interior Minister Christophe Castaner said on Wednesday.

The authorities were relentless in the search for the suspect, who they had thought was in Germany, Castaner told lawmakers.

"The excellent cooperation with the Germans enabled us to act immediately. The place where we thought he could have taken refuge was raided but he was not on this site," he added.

A total of 720 police officers, supported by two helicopters, staged a huge manhunt for the attacker, who escaped after shooting passers-by in the center of Strasbourg.

"Massive means have been deployed to arrest the presumed suspect as soon as possible," Prime Minister Edouard Philippe told the press.

France raised its security threat level to highest, strengthening controls along its border with Germany, where agents from both countries stepped up checks of motorists' identity and vehicles crossing the Rhine river.

Twenty-four hours after the attack, French police are appealing for information leading to the shooter's whereabouts and advising people "not to intervene alone".

The suspect is identified as Cherif Chekatt, 29. He has a criminal record and was known to intelligence services as "at risk for radicalization". He had been convicted 27 times in France, Germany and Switzerland for common law offenses, including armed robberies.

"He is an individual who has unfortunately been known for a very long time for crime. From the age of 10, his behavior was already criminal. He had his first sentence at age 13," Castaner said.

Armed with a handgun and a knife, the Strasbourg-born man opened fire several times near Place Kleber and the Grand'Rue, one of the city's main shopping streets where a Christmas market is held every year.

He exchanged fire with the anti-terrorism Sentinelle force that wounded him before he fled in a taxi. He fought a second time with police in the Neuhof district, according to Paris prosecutor Remy Heitz.

Two people were killed and a third individual has been pronounced brain dead in the attack. Twelve passers-by were also wounded, six of whom suffered serious injuries, Heiotz told reporters earlier in the day.

Many of the victims, aged between 20 and 65 years, were stabbed, according to Strasbourg hospital.

France remains a top target of terror attacks. Three years ago, a series of coordinated attacks, claimed by the Islamic State (IS), targeted bars, a concert hall and a soccer stadium in the French capital. About 130 people were killed and more than 350 others were wounded.

"Terrorism risk is omnipresent and we remain at a high alert level even if attacks have changed shape," Castaner told MPs.

President Emmanuel Macron chaired an emergency security meeting earlier on Wednesday after which he decided to deploy an additional 1,300 security forces to guarantee security in Christmas markets and ensure calm during the year-end holidays.