French police
© MARTIN BUREAU/AFP via Getty Images
Four police officers have been stabbed to death at a headquarters building near the cathedral of Notre-Dame in Paris, France.

The perpetrator "was involved in an argument with someone and then erupted in anger, targeting other police colleagues before being neutralised," according to a source quoted by The Sun.

"The attacker is believed to have been an administrative officer working in a secure part of the building - making it very easy for him to walk around freely. He would have had security clearance.

"One victim is dead, along with the attacker. Others are in intensive care."

French media now reports that the death toll has risen to four, however.

map of Paris

It's literally next door to Notre Dame
The attacker's motives, if known, are yet to be disclosed, as his identity.

A police union secretary, Loïc Travers, has told France's BFM TV that he was a long-term employee, who had been "with us for over 20 years". At least one of his victims was a female officer.

The attack also comes one day after French police went on a nationwide strike.

Video from the scene circulated on social media.