Four people were injured in a knife attack Friday near the former offices of French satirical magazine Charlie Hebdo, the site of a 2015 terrorist attack, authorities said.

French Prime Minister Jean Castex cut short an event in the Parisian suburb of Seine-Saint-Denis, saying that a "serious event" had taken place in the capital.

Two of those injured were in critical condition, and the suspects involved in the attack were still on the run, a Paris police spokesperson said.

A perimeter has been set up around the site and people should avoid the area, the spokesperson added.

The stabbing comes amid a trail of suspects alleged to have been accomplices to a series of January 2015 terrorist attacks that began with the killing of 12 people at the Charlie Hebdo offices and ended with an attack at a kosher supermarket two days later.