Paris police say an unidentified assailant has attacked a police officer near the Notre Dame Cathedral, and the officer then shot and wounded the attacker. The office is hurt but the extent of their injuries is unclear.

A police spokesperson tells The Associated Press the officer used his weapon to shoot the attacker. The spokesperson, who was not authorized to be publicly named, said the attacker was hospitalized.

A police union official, Cedric Michel, said a man armed with a hammer went after the police officer who was patrolling on the esplanade in front of Notre Dame Cathedral. Michel said the attacker was “neutralized” by police.

It is unclear whether the attacker was acting alone.

A chaotic scene is playing out with a large number of police cars filling the area on the Ile de Cite in the River Seine in the center of Paris.

Paris is under high security and has been for a while after a string of Islamic extremist attacks in recent years.