The army freed 20 kidnap victims from a house in Monterrey, north Mexico, after receiving an anonymous tip.

The hostages were found on Saturday. They were hand-cuffed, gagged and showed signs of torture.

According to reports, some of hostages had been held for 11 days while their captors demanded between 5,000 and 50,000 pesos in ransom ($425 to $4,250).

Security forces arrested a man guarding the victims, and handed him to Nuevo Leon state prosecutors.

The army rescued another seven hostages in Monterrey in June, along with one man who had been beaten to death.

Monterrey, a long-time drug trafficking hub, has been hit by high levels of violence since 2010, when the Gulf Cartel split from their former security wing, the Zetas.