Susana Seijas is a CBS News producer based in Mexico City.
MEXICO CITY, Mexico - Mexican authorities seized two homemade tank-like vehicles in the northern state of Tamaulipas on June 4.
The armored, one inch-thick steel-enforced vehicles are being called narco tanks, rhino-trucks, monsters and beasts.
The menacing homemade tanks look like props from the movie "Mad Max."
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Mexico's Ministry of Defense said it found the makeshift tanks at a clandestine metalworking shop in the border city of Camargo.
Authorities reported finding an additional 20 trucks being re-fitted into narco-tanks, with air conditioning and firing porholes at the Camargo metalworking shop.
The vehicles can hold up to 20 fighters, and are also used to transport people and drugs. So far there is no evidence the tanks have been used to cross the border.
El Blog del Narco, an independent blogger with often gory content of Mexico's drug war, reported that the monster trucks can go up to 60 miles per hour and were specifically made for the Zetas Cartel as they wage war with their rivals from the Gulf Cartel.
Today El Blog del Narco reports the finding of yet another narco tank in Coahuila state.
Mexican media are reporting the phenomenon of the narco-tanks as a clear signal that there is an "arms race" among the Zetas and the Gulf cartels, as they try to outwit each other with more brutal technology.
Since President Felipe Calderon took office in 2006 and declared war on Mexico's increasingly ruthless drug cartels, more than 35,000 people have been killed.