Residents gather near the site of an attack in the 18th district in Paris, on Jan 7, 2016. Police in northern Paris shot dead a man armed with knife trying to enter the police station in the French capital 18th district, according to local media. [Photo/Xinhua]

PARIS - A government official on Thursday said investigators looking into the attempted attack on police officers in the northern suburb of Paris earlier on Thursday did not yet have clear grounds to describe it as a terror act.

"It's too early to speak about a terrorist attack. We must be extremely careful. It's not because he shouted 'Allahu Akbar' (God is Great) while trying to attack policemen that he was conducting a terrorist assault," Pierre-Henry Brandet, interior ministry spokesman, told iTele news channel.

Visiting the shooting scene, Interior Minister Bernard Cazeneuve said an inquiry team was only starting to uncover the assailant's identity and motive.

Armed with a knife and wearing an explosive belt which turned out to be fake, the man tried to enter the police station to stab officers before being shot dead by one of the servicemen at about midday local time (1100 GMT), news channel BFMTV reported.

Police set up a security perimeter on the site. Two schools in were locked down and nearby metro stations were closed.

Reports said the assailant could have had a possible accomplice to conduct, on a dare, a strategically-timed attack to correspond with last year's Jan 7 attack on the satirical magazine Charlie Hebdo.

However, Brandet said the assailant was likely acting alone, but "we can not excluded that he would have a certain complicity to prepare and commit the attack," according to the interior ministry spokesman.

In a statement, Paris Prosecutor Francois Molins unveiled that the man was carrying a flag of the terrorist cell Islamic State (IS).

"A mobile phone and a piece of paper, on which appear the Daesh flag and a clear written claim in Arabic, were found on the individual," Molins said.