PARIS, June 6 (Xinhua) -- The suspect who attacked a police officer outside Notre Dame Cathedral in Paris on Tuesday was identified as an Algerian student who was believed to commit his act to revenge the war in Syria, French Interior Minister Gerard Collomb said.

"What we know at this stage that he is an Algerian student," Collomb told reporters, adding that authentication of an identity card found with the suspect was underway.

"A person armed with a hammer began to hit a policeman. His colleague opened fired, allowing the attacked policeman not to be the victim of serious violence than that he has undergone," he said.

The suspect who was also armed with knives, shouted "This is for Syria" when he attacked the policeman and slightly injured him, according to the minister.

The man, wounded in the attack, was believed to act alone. His motives remain unknown, according to the minister.

Paris prosecutor's anti-terrorism unit launched an investigation into the incident.

"In the coming days, Paris prosecutor will give precise circumstances of this aggression," he said.

"We have gone from a sophisticated terrorism to terrorism where any tool can be used for aggressions," he added.

France remains in a state of emergency and on high alert over possible terrorist attacks due to its military intervention in Syria, Iraq and the Sahel region.

France imposed emergency security rules in the wake of the 2015 attacks which killed 130 people. It also deployed 10,000 of gendarmes and police units to protect public places and sensitive sites.

However, several more attacks have occurred since, with the bloodiest on Bastille Day last year in Nice where a man drove his truck into a crowd, killing 86 people.