A woman has been stabbed to death inside a retirement home where 60 former missionaries are living in southwestern France.
There are unconfirmed reports another person has also been killed.
Local media said a man disguised with a mask or hoodie and armed with a sawn-off shotgun entered the retirement home in the village of Montferrier-sur-Lez, which was home to at least 60 retired monks.
He was reportedly still holed up somewhere in the building.
Police said they did not believe the incident was a terrorist attack.
More than 60 people who formerly worked in religious missions in Africa live at the home.
According to one source, a caretaker contacted the police after escaping from the home in Montferrier-sur-Lez about 10 kilometres north of Montpellier.
On entering the building, police found the body of an elderly woman who had been stabbed several times, the source said.
"Nothing at this stage would indicate that this would be a terrorist act," another source said.
French newspaper Le Figaro said the dead woman was found bound and gagged.
It also said that one man, "hooded and armed with a knife and sawed-off shotgun" broke into the home, citing sources close to the investigation.
Special police units have arrived at the building in the Herault area, it said, and 16 monks have been safely rescued.
France is on heightened alert and has been under a state of emergency since a wave of Islamist attacks last year.