Gunmen used a heavy truck to block a highway in the Western state of Michoacan and opened fire on a federal police convoy.

"The information we have is that there are 10 dead and several wounded," Michoacan state Public Security Minister Minerva Bautista told a local radio station.

The federal government confirmed the police deaths and said an unknown number of the assailants were killed.

Michoacan, the home state of President Felipe Calderon, has emerged as a key battleground as the cult-like La Familia cartel fights other gangs and security forces for control of the mountainous state.

At least 23,000 people, mainly traffickers and police, have been killed in drug violence in Mexico since Calderon launched his army-led and US-backed crackdown on traffickers on taking office in December 2006.

In a jail in the Pacific state of Sinaloa, rival gangs clashed and at least 17 prisoners were killed, police spokesman Martin Gastelum said.

"They all died from gunshots," he said.

Sinaloa is the home turf of Mexico's most wanted drug lord, Joaquin "Shorty" Guzman.

Local media said last Friday was the most violent day yet of Calderon's presidency with 70 drug-related killings, including the murders of 19 addicts at a rehabilitation clinic in the northern city of Chihuahua.

The violence frightens away tourists and worries the United States, which is giving anti-drug aid, equipment and police training to Mexico.

Some investors have frozen funding for factories in cities on the US border, especially in Ciudad Juarez, the most deadly place in the drug war and just across from El Paso, Texas.