Anti-terrorist police were searching for a masked gunman overnight after at least one woman, believed to be a nun, was murdered at a home for retired missionary monks in the south of France.

The bloodbath unfolded at the Green Oaks care home in the village of Montferrier-sur-Lez, north of Montpellier, soon after 9.30pm.

Shots were heard as the unidentified intruder attacked member of staff and members of an elderly religious community belonging to the Society of African Missions.

Police have put up roadblocks around the area to try and detain the killer on the run

One warden is said to have ‘discreetly raised the alarm,’ before being bound and gagged by the man, who was armed with a sawn off shotgun and a knife.

Those killed are thought to be a woman worker, who may have been a nun, who was tied up, and then stabbed three times.

Early fears that a man was also killed alongside her have not been confirmed.

Gendarmes arrived within minutes of the alarm being raised, and they were soon followed by a unit of the GIGN tactical support group.

They soon found the corpse of an elderly woman who had been tied up and then stabbed repeatedly with a knife.

‘A supervisor inside the building raised the alarm very discreetly,’ said a local police source, who confirmed that the siege ended soon after midnight.

Some fifty monks were ‘evacuated’ from the building after gendarmes searched all floors, and then gave the all clear.

The gunman, believed to be wearing a mask and dark clothing including a hoodie, was nowhere to be seen, however, and a manhunt started.

‘An individual, who was masked and armed with a knife and a sawn-off shotgun came into the retirement home where 70 monks live,’ one source said, adding that the man’s motivations were unknown.

The nursing home for monks and priests was established since 1994 run by an association Les Chenes Verts.

Speaking at a press conference, spokesman of the Archdiocese of Montpellier (Hérault) Wayne Bodkin said: ‘It’s a shock, it is unclear why such a tragedy, we have no idea of the intrusion pattern in this religious retreat house that welcomes former missionary in Africa. It is in the countryside, very quiet. ‘Most of the residents are over 70 years old.’

Montpellier prosecutor Christophe Barret told AFP ‘For the time being, there is only one victim.

‘For the moment there is no particular evidence about the motive for this crime.’

The man was not known to authorities.

Residents of the home ‘are very elderly with an average age of 75 although some are more than 90,’ said Alain Berthet, a local councillor in Montferrier-sur-Luz.

France is currently under a state of emergency following a series of terrorist attacks by Islamist terrorists .

One of the most recent was in July when an 84-year-old Catholic priest was murdered during morning mass at the parish church in Saint Etienne-du-Rouvray, a suburb of Rouen.

The two attackers, who said they were from Islamic State, slit Father Jacques Hamel’s throat before themselves being shot dead by police.