Five men arrested this week in France were planning a terror attack as early as next week and were receiving their orders from an Islamic State group member based in Iraq or Syria, prosecutors have said.
The five were arrested on Sunday, four of them in the eastern city of Strasbourg, and one in the southern city of Marseille.
Paris prosecutor Francois Molins said the Strasbourg "commando" of four was plotting a terror act on December 1 but that investigators have not yet determined "the specific chosen target among all those considered by the group".
He said the five men were "given guidance remotely" from an IS member based in Iraq or Syria and they had a "clear will to find and to identify targets to commit an act in the very short term".
Investigators found communications containing GPS co-ordinates on one suspect's USB stick.
The five men "had common instructions to obtain weapons, instructions given by an ordering person from the Iraqi-Syrian zone through encrypted applications popular among terrorists".
Mr Molins was speaking to reporters the day after anti-terrorism authorities took the unusual step of holding the men in custody without charge beyond the normal maximum period, relying on a recent anti-terrorism measure.
France remains under a state of emergency imposed after IS attacks in Paris in November last year that killed 130 people.