MEXICO CITY (AFP) – Mexicans took to the streets in their hundreds to protest a staggering surge in drug-related violent crime nationwide that claimed at least 45 lives in one weekend.

"No more violence, no more lack of safety, no more corrupt politicians, let's move ahead with citizen candidates," marchers on the touristy Paseo de la Reforma shouted after at least 45 people died in Monterrey and Guadalajara, and the northern state of Chihuahua.

Demonstrators marched to the Senate to unveil an appeal for tougher anti-drug laws.

The attacks were 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.

From late Saturday into Sunday, 15 people were killed in Chihuahua state drug-related bloodletting, prosecutors said. Of the 15, nine people were slain in Ciudad Juarez, Mexico's deadliest city across from the US city of El Paso.

Also in Chihuahua state, 11 people were slain in several separate murders in Ciudad Juarez, a day earlier between late Friday and Saturday, authorities said.

And gunmen shot dead five men together in an additional group killing on a highway between Chihuahua city, the state capital, and Ciudad Juarez, police said.

Separately, 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 Monterrey, 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.

Meanwhile, 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.

As authorities stepped up their anti-drug operations, they discovered a secret tunnel used to smugged drugs into the United States.