Officials and relatives of missing people are digging in a field in the Gulf coast state of Veracruz where they have found at least 15 bodies in clandestine graves.

The state's head prosecutor says search teams exhumed 12 sets of remains and have located three more bodies but not yet extracted them.

The searchers include volunteers from victims' groups. Prosecutor Jorge Winckler said Tuesday that the teams found several other suspected graves in the township of Rio Blanco.

Hundreds of clandestine graves have been found in Veracruz, where drug cartels and kidnapping gangs dumped the bodies of rivals and victims.

Victims' groups have taken the lead in searching because of authorities' inaction, and often receive tips about burial sites.