Mexican policemen stand guard next to an armoured car seized to alleged members of the Mexican drug cartel "Los Zetas".The armoured car called "The Z Monster" has a capacity to transport about 20 men and has a turret to place. (HECTOR GUERRERO/AFP/GETTY IMAGES)

For the drug cartel boss who has everything, the latest piece of military hardware is the “narco tank.”

Today’s competitive crime mafias in Mexico are no longer satisfied with bazookas, rocket-propelled grenades or land mines. The Mexican military has discovered that gangsters south of Texas are building armored assault vehicles, with gun turrets, inch-thick armor plates, firing ports and bulletproof glass.

More than 35,000 Mexicans have died in four years of drug violence, and the fighting between the rival Gulf and Zeta cartels, and with the military units that chase them, has been especially vicious in the border cities and farm towns of the northern state of Tamaulipas. Just two days ago, two mutilated bodies were left hanging from a pedestrian bridge in Monterrey.

“Organized crime has increased its firepower to move personnel and mount counterattacks against the army,” said Alberto Islas, a security adviser in Mexico. “This is the consolidation of an urban guerrilla war scenario.”

The Mexican media and military call the assault vehicles “monstruos,” monster trucks. In Mexico, their appearance on the Internet has gone viral. On the front page of Reforma, a national daily newspaper, a photograph Monday of a monster truck was accompanied by the headline: “And this doesn’t look like a war?”

The Mexican army announced Sunday night that a military convoy on routine patrol raided a warehouse in Camargo, Tamaulipas, across the border from Rio Grande City, Tex., and seized two dump trucks that had been rigged with steel plates to protect gunmen.

The monsters look like a cross between a handmade assault vehicle used by a Somali warlord and something out of a post-apocalyptic “Mad Max” movie. Complete with battering rams.

The assault vehicles have appeared in several confrontations with Mexican authorities. In the western state of Jalisco, soldiers confronted one of the beasts in May and disabled it by shooting out its tires. The trucks have not been seen in the cities and remain mostly a chilling curiosity.

The popular and lurid “narco blog” Web site said the armored truck could do 60 mph and dump — James Bond style — tire-popping nails or oil slicks to slow down its pursuers.

“These behemoths indicate the ingenuity of the cartels in configuring weapons that are extremely effective in urban warfare,” said George Grayson, a professor at the College of William and Mary and a specialist in Mexico’s drug war.

The cartels are locked in a kind of arms race involving technology and techniques to keep one step ahead of authorities — and one another.

Last year authorities found an elaborate tunnel stretching more than 2,200 feet, complete with train tracks and ventilation, that was used to move marijuana between a house in the Mexican city of Tijuana and a warehouse in Otay Mesa, Calif.

On the high seas, maritime forces have intercepted dozens of “narco-submarines” hauling multi-ton loads of cocaine north. The semi-submersibles travel very low in the water to avoid detection.

With growing frequency, U.S. guards have spotted ultralight aircraft barnstorming over the border fences to drop 200-pound loads of pot in fields for waiting pickup trucks that flash their high beams or create a makeshift drop zone out of light sticks. According to U.S. officials, there have been more than 300 ultralight incursions into the United States in the past 18 months.

U.S. and Mexican border agents have found ramps, tunnels, and even a catapult that was used to lob drugs over the border fence between Mexico and Arizona.

Narco tanks might look odd, but they are further proof of a serious and deadly arms race among cartels.

Mexican soldiers last week discovered a major arsenal of weapons and ammunition in an underground bunker, probably buried by the Zeta crime organization.

The cache of 150 rifles, pistols and shotguns, 92,000 rounds of ammunition, four mortar shells and two rocket-propelled grenades was discovered at a ranch in the northern state of Coahuila, which borders the United States.