By MICHAEL WEBSTER: Syndicated Investigative reporter. Feb 18,  2009 at 1:30 PM PST.

Police use a water cannon to disperse protesters in the northern industrial city of Monterrey, Mexico, where hundreds of protesters in Monterrey and others in several border cities demanded that the Mexican army leave their cities. Officials say that the protests are organized by Mexican drug cartels that they say are trying to disrupt the government's anti-drug crackdown. (AP Photo) - AP

Mexico -- Thousands of Mexicans are protesting in Mexico City and others are blocking roads and bridges into the U.S. They are protesting army operations against drug gangs that officials said was organized by the Mexican drug cartels.

The protesters are demanding the army leave in another challenge for the Mexican government as it struggles to quell escalating drug violence since the Calderon administration ordered Mexican army troops into Mexican Border cities and many other cities throughout Mexico.

Mexican newspapers are reporting several hundred protesters carried signs in the streets of Mexico. In the northern city of Monterrey' in front of the town hall protesters signs read in Spanish "Army Get Out! In a growing challenge to the military across Mexico, groups of taxi drivers, shop keepers and Mothers also blocked bridges that connect the border cities of Juarez, Tijuana and  Reynosa with U.S. Cities, stopping vehicles and foot passengers, police said.

The protestors in Ciudad Juarez and Tijuana blocked traffic for hours across three bridges connecting the city to El Paso, Texas, and California with Mexico. Similar protests broke out on bridges in the border cities of Nuevo Laredo and Reynosa, while demonstrators blocked roads in Mexico City.

It was the largest display of discontent against the army's role in an anti-drug crackdown since President Felipe Calderon began deploying soldiers across the country two years ago to fight Mexican drug cartels. About 45,000 soldiers are now spread out across Mexico.

According to AP government and army officials claimed that drug cartels organized similar protests in Monterrey earlier this month to undermine the crackdown. Federal officials had no immediate comment on the protests.

Human rights activists say there are legitimate complaints about abuses by soldiers, including cases in which patrols opened fire on civilians at military checkpoints. But they say it is unclear who has been behind the demonstrations.

El Paso Times reports that the Calderon's offensive was initially widely popular among Mexicans hopeful for an end to relentless shootings, kidnappings and killings. But drug violence has only surged and become more violent since he took office, with drug gangs beheading rivals and attacking police nearly every day. More than 6,000 people were killed in drug violence last year.

Border towns have been transformed by the crackdown, with soldiers in ski masks regularly rumbling down the streets in large convoys.

Some of the protestors, mostly women and children, blocked the Paso del Norte bridge leading from Ciudad Juarez to downtown El Paso. They shouted "soldiers, get out!" as they stood in front of about 20 troops in green army pickup trucks. One person held a sign reading, "Get out of Juarez, thieving abusive soldiers."

Brenda Contreras, a 22-year-old mother of two, said the city has only become more dangerous since troops arrived. She said soldiers detained her 32-year-old husband during a raid at a car wash three months ago, and she has not heard from him despite filing a complaint with the Defense Department.

"I saw him on the floor and they wouldn't let me get near him. Where he is, only the army knows. What am I going to tell my daughters?" she said.

Not all city residents, however, are against the army's presence.

"Knowing that the soldiers are out there all over the city makes me feel that the city is more protected," said Cynthia de los Santos, 32, a secretary at a Ciudad Juarez law firm.

In Nuevo Laredo, 150 people blocked three bridges leading to Laredo, Texas, for several hours. Many were masked men, but some were women and children.

Protesters also blocked bridges leading to Texas from Reynosa, the town's mayor, Oscar Luebbert, told Mexico's Radio Formula.

Luebbert also said a shootout erupted Tuesday between federal police and armed men in Reynosa, and authorities were trying to confirm reports that several people were killed.

"The situation is very critical," Luebbert said. "The whole population is very alarmed."

An official from the federal Public Safety Department said the shootout erupted when federal police came across a group of gunmen. Soldiers joined the fight when police asked for help, said the official, who was not authorized to give his name. He said at least four gunmen were killed and several police were injured.

Protesters also blocked two highways in the Gulf coast state of Veracruz and one road outside the state capital, Jalapa.

Nuevo Leon state police Chief Aldo Fasci said last week that crime organizations were paying people to protest against the army and that gangs were handing out backpacks full of school books, pens and paper to poor families who joined the demonstrations.

This recent protesting by the people of Mexico is spreading around the world, explosive anger is spilling out onto the streets of Europe. The meltdown of the global economy is igniting massive social unrest in a region that has long been a symbol of political stability and social cohesion.

It’s not a new trend: A wave of upheaval is spreading from the poorer countries on the periphery of the global economy to the prosperous core.

Riots are spreading across what is patronizingly known as the Third World. Furious mobs have raged against skyrocketing food and energy prices, stagnating wages and unemployment in India, Senegal, Yemen, Indonesia, Morocco, Cameroon, Brazil, Panama, the Philippines, Egypt, Mexico and elsewhere.

For the most part, those living in wealthier countries took little notice. But now, with the global economy crashing down around us, people in even the wealthiest nations are mad as hell and reacting violently to what they view as an inadequate response to their tumbling economies and incompetent political leaders.

In the mean time the police chief of the Juárez police department and three officers were killed in an ambush Tuesday.

Police operations director Sacramento Perez Serrano, 49, was being escorted by the officers when the four-door police pickup they were riding in was riddled with gunfire in the upscale Zona Dorada (Golden Zone) area of the city about 5 p.m.

Perez and the three officers died in the attack near Paseo de La Victoria and Ejercito Nacional boulevards.

"They were on their way to the Babicora (police) station when they were ambushed by an armed commando," said Jaime Torres, city spokesman.

"They didn't have a chance to defend themselves. They died in the patrol unit."

Police, federal agents and soldiers are on "red alert" as an extensive man hunt for the killers continues, Mexican officials said.

More protests are expected country wide in Mexico, according to Mexican officials.