MARSEILLE, France (AP) — A man with a knife attacked people at the main train station in the southeastern French city of Marseille on Sunday, killing two women before soldiers fatally shot the assailant, officials said.

French police warned people to avoid Saint Charles train station, tweeting that an operation was underway. Soldiers and police took up positions outside the station, which was evacuated.

Three police officials said one woman was stabbed to death. Two of the officials said the other woman's throat was slit. The assailant was shot dead by soldiers who were patrolling the station. The officials were speaking on condition of anonymity because they weren't authorized to speak publicly about the operation.

Paris prosecutor's office said that a counter-terrorism investigation has been opened. No further details were immediately given, including the motive for the attack.

Interior Minister Gerard Collomb tweeted that he would travel to the scene.

About 7,000 French soldiers patrol major tourist sites, places of worship, train stations and airports across France. The so-called Sentinelle Operation has been in place since deadly extremist attacks in France in 2015.

Earlier this month, four American college students were attacked with acid at the same train station in Marseille. At the time, French authorities said the assailant was suffering from a mental illness and it was not investigated as a terror attack.

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Sylvie Corbet reported from Paris. Associated Press writer Philippe Sotto contributed to this report from Paris.