Four gunmen died when they crashed into a toy store during a police chase in Mexico's Nuevo Leon state over the weekend, while four inmates died in a fight at a prison in Chihuahua state, officials said.

Police chased and exchanged gunfire with gunmen Sunday in Guadalupe, a city in the Monterrey metropolitan area, a municipal police spokesman told Efe.

The four gunmen died when they lost control of their SUV and crashed into a toy store at a shopping center.

Firefighters had to use special equipment to remove the bodies from the mangled vehicle.

An automobile that was also involved in the chase was found abandoned with bloodstains in the interior, police said.

Nuevo Leon, whose capital is Monterrey, and neighboring Tamaulipas state have been rocked by a wave of violence unleashed by drug traffickers battling for control of smuggling routes into the United States.

More than 1,100 people, including about 80 police officers, have died in the violence in Nuevo Leon in the past year.

The violence has intensified in the two border states since the appearance in Monterrey in early 2010 of giant banners heralding an alliance of the Gulf, Sinaloa and La Familia drug cartels against Los Zetas.

Heriberto Lazcano Lazcano, known as "El Lazca," deserted from the Mexican army in 1999 and formed Los Zetas with three other soldiers, all members of an elite special operations unit, becoming the armed wing of the Gulf drug cartel.

After several years on the payroll of the Gulf cartel, Los Zetas went into the drug business on their own account and now control several lucrative territories.

Four inmates, meanwhile, were killed and several others wounded in a fight involving members of rival gangs at a prison in Chihuahua city, the capital of the like-named northern state, police said.

The fight started Sunday, when the rival gang members fought with homemade knives.

Federal officials are taking control of the prison because most of the inmates are serving sentences for violations of federal crimes, Chihuahua Gov. Cesar Duarte said Friday.

Chihuahua's prisons are frequently the scene of fights between members of rival gangs that work for drug cartels.

A total of 15,270 people died in drug-related violence in Mexico last year, and nearly 40,000 people have died since President Felipe Calderon declared war on the country's cartels shortly after taking office in December 2006.

Calderon has deployed tens of thousands of soldiers and Federal Police officers across the country to combat drug cartels and other criminal organizations.

The anti-drug operation, however, has failed to put a dent in the violence due, according to experts, to drug cartels' ability to buy off the police and even high-ranking officials.