People in several cars were exchanging gunfire and police began to chase them, Guerrero state police said. Soldiers also joined the hunt.

Officials said the gunmen shot at their pursuers, then some abandoned their cars and fled on foot. They were chased to a cockfighting ring and six were found dead there. Three others were found dead or dying in the cars.

It is unclear whose shots caused the deaths.

Police also reported two dead in the state's largest city, Acapulco. They were found shot to death on a major avenue, possibly after an attempt to hang them from an overpass.

Drug gangs were suspected in both incidents.

Also Monday, five gunmen were killed in a firefight and car chase with soldiers on a highway near Laredo, Texas.

Soldiers gave chase after an SUV they were inspecting pulled away and the passengers started firing at them, said prosecution officials in the northern state of Nuevo Leon.

The gunmen were shot while trying to escape their vehicle after it swerved off the Laredo highway and crashed into a ditch.