Mexican authorities have discovered as many as 48 bags containing human remains from a clandestine grave near Guadalajara, the capital of Jalisco state.

Guadalajara is where one of Mexico’s most violent and powerful drug cartels operates and where thousands of people have been reported missing.

The bags with the remains were located by a search group on a vacant lot in Zapopan, a vast outlying municipality in the Guadalajara metropolitan area.

Officials said they were still trying to pin down an exact number for victims whose remains were found in the bags. They declined to give an estimate, but said they were carrying on with a search to see if more remains were around.

In presenting an official report on the search efforts, deputy state prosecutor for missing persons, Blanca Trujillo, told a press conference that the search has required the use of heavy machinery because of the vastness of the land.