A running battle between police and gunmen has left 12 people dead in this central Mexican city, officials said Friday.

The dead included three police officers and nine gunmen, said Hidalgo state Attorney General Jose Alberto Rodriguez. Two state police officers and one city officer remained hospitalized Friday after suffering gunshot wounds in the attacks late Thursday on the outskirts of Pachuca.

A state officer, who was also wounded, died Friday at the hospital.

Hidalgo state police director Donanciano Millan said officers were acting on a tip that gunmen were in the area when they stopped four trucks carrying the assailants, who opened fire and fled. Officers pursued them, and the two groups exchanged gunfire.

After the attacks, police seized assault rifles, grenades, federal police uniforms, handcuffs and about 7 pounds of cocaine.

Police were searching the area for more suspects Friday.

Elsewhere, gunmen killed a regional police investigator outside his home Thursday night in the border city of Ciudad Juarez, across from El Paso, Texas, said state police spokesman Arturo Sandoval.

Drug violence has killed more than 11,000 people since Mexico launched a national crackdown in 2006. The government says most of the victims have been killed in turf battles with rival cartels fighting for control of lucrative drug routes.