A shootout between police and gunmen killed 12 people on Friday in the central Mexican state of Guanajuato, the state's governor said.

At least one police officer was wounded in the clash, Gov. Juan Manuel Oliva said.

Oliva said that soldiers and federal and state police were on patrol in the town of Apaseo el Alto when assailants opened fire. Local media reported that all the dead were gunmen but Oliva didn't confirm that.

Oliva said arrests have been made, but he gave no other details.

Mexico has been suffering a wave of gang violence that has left more than 10,800 people dead since President Felipe Calderon took office in December 2006, and launched a military-led crackdown on drug traffickers.