MONTERREY, Mexico (ANTARA News/AFP) - Eight people were killed in a gun battle Saturday between police and criminals in the northern Mexican city of Monterrey, while at least six died when a grenade exploded in Guadalajara, police said.

The attacks are the latest deadly violence gripping Mexico`s war on drugs, as the country`s various criminal cartels struggle over turf and the government uses police and soldiers in an attempt to crush them.

Around 4:00 am (1000 GMT) a special unit of soldiers and police known as the Immediate Reaction Group stopped two suspicious vehicles in a suburb of the industrial city of Monterey, the Secretariat of Defense said.

The car occupants responded by pulling out weapons and opening fire.

"Seven alleged aggressors lost their lives" in the shootout, the

secretariat said in a statement, adding that the attackers "struck the side of a vehicle, resulting in a civilian death."

Monterrey, a prosperous city and home to the local operations of several multinational corporations, is at the intersection of several highways -- often used as drug smuggling routes -- heading north into the United States.

Two rival drug organizations, the Gulf cartel and their former allies, the Zetas, are battling for control of the area.

Separately, at around the same time an unknown assailant threw a

fragmentation grenade at the porch of a crowded bar in the western city of Guadalajara, police told reporters.

Gunmen opened fire at the bar, which was packed with customers, then fled in several cars.

Three women and three men were killed in the attack and more than 20 were wounded, police said.

Drug gangs have escalated a violent turf war in the past weeks in Guadalajara, Mexico`s second most populous city with 4.4 million residents.

This is the second grenade attack on a Guadalajara bar in less than a month: on January 16 an argument between gunmen and musicians ended in a blast that killed two people.

More than 34,600 people have died in drug trafficking related violence since December 2006, when the government of President Felipe Calderon deployed soldiers and federal police in a widespread crackdown on the illegal cartels.