24 July 2010 Last updated at 03:21 ET

Mass grave in northern Mexico contains 38 bodies

Soldiers in Mexico have uncovered a mass grave with at least 38 bodies in the northern state of Nuevo Leon.

Security forces said an anonymous tip-off led them to the site almost the size of a football pitch.

Investigators believe drug gangs used the remote spot to torture and kill their victims.

In the past weeks, two more such graves have been discovered in Nuevo Leon, which is at the centre of a violent battle between rival drug gangs.

The bodies were found in a pit, east of the city of Monterrey, measuring 70 metres by 40 metres.

They were too badly decomposed for immediate identification.

Crime scene investigators are using diggers to search for more bodies, and Nuevo Leon state Attorney General Alejandro Garza y Garza said officials still had to inspect three more pits for bodies.

Torture

Investigators said the layout of the site, with large amounts of blood found along an earthen ramp and traces of petrol found at the bottom, suggested the victims were led half-way along to the pit, where they were tortured and killed.

Their bodies were then thrown into the 20m-deep pit. Photographs showed charred spots on the soil suggesting some bodies may have been partially burned.

More than 200 people have disappeared in the border state over the past three years.

Nuevo Leon has seen an increase in violence which police say stems from a deadly fight between the Gulf cartel and their former gang of hit-men, the Zetas, for control over the lucrative drug routes to the United States.

More than 24,800 people have died in drug related violence in Mexico since the government launched a crackdown in December 2006.