By Tim Johnson

MEXICO CITY — Mexico's rival crime gangs are in an arms race, and the latest sign of that are the homemade "Mad Max" type heavily armored vehicles they deploy to withstand fierce clashes with each other.

The army found two more "narco tanks" over the weekend in Ciudad Camargo in Tamaulipas state along the border with Texas.

In earlier discoveries in April and... http://www.mcclatchydc.com/2011/06/06/115327/mexican-drug-gangs-building...