French Prime Minister Manuel Valls has warned France it is facing its most significant terror threat in history.

We have never had to face that kind of terrorism in our history.

During an announcement on France Inter radio, Valls said police had thwarted five terror attacks in France recently.

Sid Ahmed Ghlam, a 24-year-old student from Algeria, has been arrested for allegedly planning the latest foiled plot. It is said to have been focussed on churches in the southern Parisian suburb of Villejuif.

“We have never had to face that kind of terrorism in our history,” Valls said. “He didn’t act alone. We saw that with the attacks (in Paris) in January. There are networks, there are those who bring logistical support. So the investigation must continue with a lot of determination, but also with the necessary secrecy in order to be as efficient as possible.”

According to officials, Ghlam was found in possession of Khalashnikovs, hand guns and ammunition. Police reportedly found literature on al-Qaeda and the ISIL militant group in his car.

Reactions among his neighbours were mixed. One person expressed concern that a man with Kalashnikovs had been living on the floor above his home.

Another said:

“I don’t think people should constantly question what could be happening, because otherwise you’d live in fear all the time. The police are here, we have security in place, they’ve been very nice to us throughout the whole process.”

Ghlam is also suspected of fatally shooting 32-year-old Aurélie Châtelain in Villejuif on Sunday (April 19).

His time in police custody has been extended by a further 24 hours under a special law applied those believed to be “at serious risk of carrying out imminent terrorist action in France.”