A suspected killer has been arrested, accused of planning to carry out imminent armed attacks on churches in Paris, the French interior ministry said.

The 24-year-old IT student – who is also a suspect in the killing of a female fitness instructor in the city – was arrested on Sunday (April 19) in possession of a significant arsenal of weapons, the authority revealed.

"A terrorist attack was foiled on Sunday morning," said France's interior minister Bernard Cazeneuve in a media briefing, revealing that "one, maybe two churches" in Paris had been targeted.

"On Sunday morning in the 13th arrondissement of Paris the police discovered an arsenal in his car and at his home composed of several military weapons, consisting of handguns, ammunition, bulletproof vests and hardware and telephones" said Cazeneuve.

The man had come to the attention of security services after making inquiries about travelling to Syria and was placed under surveillance, reports Reuters,

He is suspected of being involved in the killing Aurelie Chatelain, 32, who was found dead in a car in the Parisian suburb of Villejuif on Sunday, with his DNA being found at the scene of the crime.

France has been on a state of high alert since the Paris terror attacks in January on satirical magazine Charlie Hebdo and a kosher bakery in which 17 people were killed.

Hundreds of French citizens are believed to have travelled to Syria to fight for extremist Sunni organisation Islamic State.