Report: Knife attack at French train station; assailant shot

French police have warned people to avoid Marseille's main train station amid reports of a knife attack.

Marseille police said an operation "is underway" on its official Twitter account. No other details were immediately available.

French television BFM TV says at least one person has been stabbed, and the assailant has been shot dead.

Interior Minister Gerard Collomb tweeted that he's going immediately to the scene "after the attack perpetrated near Saint Charles train station."

The train station has been evacuated.