Four young men have been arrested and indicted in the French city of Rouen on charges of forcing at least four underage girls into prostitution.

The suspects aged 16 to 22 were arrested on Sunday and are believed to have formed a pimping gang and forced the underage girls, whom they had kidnapped, to engage in as many as 15 sex acts per day, radio broadcaster Tendance Ouest reports.

“One of the accused was already in pre-trial detention and the other three have been placed under judicial supervision,” said Rouen public prosecutor Pascal Prache.

The four suspects are accused of forcing the underage girls, whose identities and ages were not disclosed, to be sexually abused for money for several months, with as many as 15 acts per day at an average price of 100 euros.

Underage Prostitute Forced to Have Sex 200 Times in Five Days in Paris Suburbs https://t.co/P75LXIHIz3 — Breitbart London (@BreitbartLondon) December 10, 2019

“The cases started in apartments located on the Hauts de Rouen before also taking place in an accommodation in downtown Rouen. The victims were young girls who ran away or lived in foster homes. At this stage, there are at least four,” a police source said.

Investigators say the gang had been active since the start of 2019 and that the investigation that led to their arrests started in February when an alleged victim testified at the Le Havre police station.

The arrests come just days after five men in Chaperon-Vert Gentilly, a suburb of Paris, were arrested after they kidnapped a 16-year-old and forced her to engage in as many as 200 sex acts in a five day period.

The suspects in the case were also young men, aged 17 to 22, and were previously known to police.

Child sex abuse and child prostitution have become a pressing issue in areas like Seine-Saint-Denis, a “no-go zone” suburb of Paris.

A report released last month claimed that a third of the underage prostitutes in the suburb were under 15, with some of them as young as just six.

Illegal Migrant Population in Paris No-Go Zone Suburbs Hits 400,000 https://t.co/XMNN5SOHB4 — Breitbart London (@BreitbartLondon) July 6, 2018