MEXICO CITY - Another four bodies were pulled from a pair of clandestine graves in Mexico's northwestern state Durango Thursday, officials said.

State judicial officials told reporters that 30 bodies had been found in a residential area of the state capital, Durango city, since April 11.

Durango Attorney General Ramiro Ortiz Aguirre said the state morgue had overstretched its capacity since more bodies had been discovered.

Durango state is located on high-altitude plateau with many remote mountainous settlements, where local economies had long been sustained by cultivating drugs such as opium poppies and marijuana.

Durango was the setting of numerous Western movies due to its beautiful scenery, but had been beset by drug violence for years.

Mass graves containing presumed victims of organized criminal groups had been found in Mexico in recent months.

Graves containing 145 bodies were exhumed in the northeastern state of Tamaulipas earlier this month. The victims were taken at gunpoint from busses traveling in the state in late March and then murdered.