Four police employees were killed in a knife attack at Paris police headquarters on Thursday, according to city prosecutor Remy Heitz.

The three policemen and a female police administrative worker were killed by a fellow member of staff, who was later shot dead, authorities told CNN.

The incident took place inside the building, which is located near Notre Dame Cathedral on the Île de la Cité in central Paris.

One victim is undergoing surgery, said French Interior Minister Christophe Castaner. He did not elaborate on the victim's condition or injuries.

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