Authorities in Mexico have uncovered the remains of at least 51 people on the outskirts of the country's third largest city in what authorities believe is a gangland body dump.
Authorities announced the figure on Saturday as investigators in Monterrey moved into the area with heavy equipment to search for more bodies at the rural site.
Photographs from the site showed charred spots on the soil, suggesting at least some of the bodies, which were discovered on Thursday, may have been burned before being buried.
"There are some that can be identified, but others are not in good condition and we will have to run DNA tests," Eduardo Saucedo, director of investigations of Nuevo Leon state prosecutors, said.
The pits will now be inspected for more bodies, he said.
Drug cartels
Al Jazeera's Rachel Levin, reporting from Mexico City, said the government has speculated that the deaths could be linked to the country's powerful drug cartels.
But she said that is difficult to prove.
"In order to do successful DNA testing on these bodies the government would have to have a database of DNA of the families members of the bodies, and they don't have such an extensive database.
"What often happens in these situations is that these bodies are never identified. So we don't really know who they are or why they ended up there."
Government offensive
It is not clear how the dumping-ground was discovered. Drug related killings have become increasingly common in Mexico in recent years, with cartel hit men known to use mass dumping sites to dispose of their victims.
In May, police in the central Mexico tourist town for Taxco found 55 bodies in an abandoned silver mine.
The Mexican government has taken a hard line against the drug cartels, launching a major offensive against them in 2006.
But the operation has had limited success, with almost 25,000 people being killed since the operations began.
Felipe Calderon, the Mexican president, described the gangs as the "greatest threat to the well-being and progress of Mexican families".