French police are investigating what they say is the gang rape of a 19-year-old woman broadcast on social media.

The victim was attacked by four men by a nightclub in the southern city of Toulouse, on Saturday night or Sunday morning, reports said.

Videos of the incident, which appeared on Snapchat and Twitter on Monday, have been blocked by police after social media users reported it.

Investigators have now identified the woman, who confirmed the attack.

Prosecutors said there was no doubt that a crime was committed. They were not yet sure if the victim had decided to file a report, but insisted "the investigation would take place whether there is a case or not".

Police are now looking to identify at least four perpetrators, aged between 25 and 30, seen in the parking lot of a nightclub in Balma, a suburb east of Toulouse.

'Stop filming, it's rape'
According to media outlets that have watched the social media footage, the victim, who is visibly drunk, can be heard crying.

Other voices, believed to be those of the attackers, clearly suggest they are taking part in sexual assault.

Another clear voice warns the others: "Stop filming, it's a rape... it's a rape, it's a rape."

The young woman, who is partly naked, is pulled by the hair, including by a suspect who repeatedly urges her to perform oral sex.

Social media users were horrified by the images circulated online, and many reported them to the police's cyber crime division.

On Twitter, police thanked people for not sharing footage showing "non-consensual sexual acts".

Prosecutors said they were also investigating whoever filmed and shared the footage of the incident.