A message posted to the social networking site Facebook helped save a young woman from sex slavery in southern Italy and led to the arrests of three men.

The 23-year-old woman was forced to work as a prostitute in the Sicilian coastal city of Messina, but a female friend used Facebook to alert the outside world to the woman's plight.

"The victim managed to escape from her tormenters with the help of a friend of hers, who raised the alarm on Facebook," police said in a statement.

The woman had been forced into prostitution earlier this year by a 55-year-old man named as T.O., who was arrested along two other men from eastern Sicily, S.A., aged 41 and I.D., aged 48.

She had begun a relationship with S.A., who is married with three children. But when S.A. discovered she was working as a prostitute, he mistreated her, taking her earnings and beating her when she refused to have sex with him, according to police.