Drug barons wheel out the heavy artillery

Rhino trucks, narco tanks, Mad Max replicas? No one can agree on what to call the armoured monster vehicles that Mexican criminal groups have been welding together in recent months, but this much is clear - they are building more of them.

Over the weekend, Mexican authorities found two more of these makeshift road warriors in Tamaulipas, the same northern border state where the first armoured vehicle appeared in April after a battle between the Gulf Cartel and the Zetas gang.

In the latest case, the Mexican defence department said yesterday, the armoured trucks were found in a metal-working shop in Camargo, which also held at least two other partly modified monsters and 23 additional trucks.

The completed versions were bigger than those previously discovered. Built on three-axle truck beds, they had room for at least a dozen armed men, one official said. They were covered with inch-thick steel, which could withstand 50-calibre heavy machine-gun fire, and each had been equipped with insulation. Police said it would take anti-tank weaponry to immobilise one.

Sanho Tree, a drug policy expert at the Institute for Policy Studies, a Washington-based research group, said the vehicles reminded him of the Monitor and the Merrimack, two American warships that fought the first naval battle between ironclad ships during the US Civil War.

"This is first-generation technology, like the Monitor and Merrimack," he said. And because the drug business evolving so rapidly, he added, as submarines replace smuggling boats, and lighter, quieter aircraft replacing heavy, loud one, the trucks will quite probably mutate to include "shielding for tyres, their Achilles' heel, blast pads in the flooring and up- armouring."

The Mexican Army officials do not seem particularly intimidated. They have criticised the machines for being difficult to manoeuvre, noting that they are designed to frighten rivals.

But for most Mexicans, the mere sight of the seized narco-rhino monsters in military photographs offers a stark reminder that in the country's battle against crime there is no place more dangerous than Mexico's roads.

In recent years, soldiers deployed in the northern Mexican border areas have discovered 109 home-made armoured vehicles -- including one christened the "Popemobile" because it carried an armoured cabin similar to that used to protect Pope Benedict XVI on foreign trips.

In May, police in the western state of Jalisco carrying out a sweep against the Los Zetas drug cartel discovered an armoured vehicle large enough to carry 20 armed men and also equipped with weapons portholes.

Members of the Gulf Cartel and the Zetas are engaged in a bitter fight to control the lucrative smuggling routes in eastern Mexico into the United States.

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.