French police (file)
French police (file) Reuters

French police were hunting Thursday for possible accomplices to an Algerian whose plan to attack churches was foiled when his arsenal of weapons was uncovered, AFP reported. 

Prime Minister Manuel Valls said the planned attack on one or more churches in the town of Villejuif just south of Paris was the fifth to be thwarted since a terrorist killing spree in the capital left 17 dead in January.

"The threat has never been as high. We have never had to face this kind of terrorism in our history," Valls told France Inter radio.

Sid Ahmed Ghlam, 24, was arrested on Wednesday after police stumbled upon his plans when he called paramedics saying he had accidentally shot himself in the leg.

An arsenal of four Kalashnikov rifles, several handguns and bulletproof vests were discovered in his car and at his apartment as well as jihadist literature mentioning Al-Qaeda and Islamic State.  Detailed plans to carry out an attack were also found.

Police said his DNA was also linked to the murder of a young mother in Villejuif who was found shot dead in the passenger seat of her car on Sunday.

Ghlam, a young IT student with no criminal record, had previously drawn the attention of French intelligence agents over his postings on social networks expressing his desire to join terrorists fighting in Syria.

However a probe by intelligence services found nothing to go on, according to Interior Minister Bernard Cazeneuve.

Investigators are now focusing on whether Ghlam was acting alone.

Analysis of his communications equipment indicated Ghlam "was in touch with another person who could be in Syria on how to carry out an attack, with the latter clearly asking him to target a church," said Paris prosecutor Francois Molins.

"This type of individual does not act alone," said Valls.

Police are also trying to figure out the mysterious link to 32-year-old Aurelie Chatelain, who was found shot in the passenger seat of her vehicle, with her laptop still plugged in.

Several of Ghlam's friends and family have since been detained. However, his sister told AFP that her brother was not an extremist. "My brother did not change. He was not radicalized. I am shocked by all that, we do not believe it."