Suspect Shot and Wounded after Attacking Police Outside Notre Dame Cathedral

Paris police say a suspect was shot and wounded on Tuesday after attacking an officer outside Notre Dame cathedral. The Paris Police tweeted an alert urging people to avoid the area.

Police have urged people to stay away from Notre Dame and the island located in central Paris known as Île de la Cité. Numerous police cars have filled the area and an ambulance was seen leaving the scene.

A police union official, Cedric Michel, said a man armed with a hammer attacked a police officer who was patrolling in front of the cathedral. Michel said the attacker was then "neutralised" by police and taken to hospital.

Prosecutors say they have opened an anti-terrorism probe into the incident.

The cathedral was placed on lockdown and visitors took shelter inside as the police operation was under way in the square.

France remains in a state of emergency and at its highest terror alert level after a series of terrorist attacks in recent years. Smaller, "lone wolf" attacks have often targeted the security forces. A police officer was killed and two others were wounded on April 20 when an attacker opened fire on their vehicle on the Champs-Élysées avenue.

In February, a man armed with a machete in each hand attacked soldiers on patrol at the Louvre Museum. In March, a 39-year-old man was killed at Paris's Orly airport after attacking a soldier.

Thousands of troops and armed police have been deployed to guard tourist hotspots such as the Champs-Élysées or other potential targets, including government buildings and religious sites.

In January 2015, gunmen killed 17 people in attacks at the Charlie Hebdo satirical magazine and a Kosher supermarket. Several bars and restaurants in Paris, including the Bataclan concert hall, were targeted in attacks that left 130 dead on November 13 of that same year. A truck rammed through a festive crowd gathered for a Bastille Day fireworks display in Nice in July 2016, leaving more than 80 people dead.