Three police officers and a support staff member have been killed by a fellow employee in a knife attack at a police headquarters in Paris.

The 45-year-old attacker, who was said to have worked for the police for 20 years, was shot dead at the scene.

It happened at about 1pm local time at the large police building located just across from Notre Dame Cathedral.

Initial reports stated four police officers were killed, but it has since been confirmed one victim was an administrator.

Police union official Loic Travers said the attack appeared to have started in an office and continued elsewhere in the compound.


Image: The attack happened at lunchtime on Thursday

He said the employee believed to be responsible was an administrator in the intelligence unit who had never created any problems before.

The attacker had also recently converted to Islam, according to the French news channel BFM TV.

The motive isn't yet known, but officers have ruled out terrorism for now.

Mr Travers said he could not remember an attack of this magnitude against officers before.

Emery Siamandi, another employee, told Associated Press he had heard gunshots and saw two officers come out of an office in tears.

Image: Paramedics and firefighters are seen in front of the headquarters where the officers were killed

He said a third officer, described as the person who shot the attacker dead, came out on his knees, also in tears.

The Paris prosecutor said the victims were three men and one woman.

The neighbourhood was locked down after the attack and the Cite Metro station closed.

The motive is unclear but another police union leader, Jean-Marc Bailleul, described it as a "moment of madness" rather than terror.

Image: An air ambulance landed on the nearby on the Pont Marie

Other media reports in the country have said the suspect had "tensions" with his supervisor.

The attack came a day after thousands of officers marched in Paris to protest against low wages, long hours and increasing suicides in their ranks.

President Emmanuel Macron is due at the scene with the interior minister and the Paris prosecutor.

"Paris weeps for its own this afternoon after this terrifying attack in the police headquarters. The toll is heavy, several officers lost their lives," tweeted the city's mayor Anne Hidalgo.

French police have been targeted by extremist attacks in recent years. A gunman opened fire on the Champs-Elysees in 2017, killing one officer before being killed himself.

In 2016, an Islamic State-inspired attacker killed a police officer and his partner at their home in front of their three-year-old child.