Army troops found 154 assault rifles and other armament inside a drug cartel's underground arsenal in the northern state of Coahuila, Mexico's defense department said Friday.

Intelligence work led soldiers under the command of the 6th Military Zone to a field in the municipality of San Buenaventura, the department said in a statement.

Once at the scene, troops discovered the entrance to the clandestine arsenal.

Besides the assault rifles, the soldiers confiscated seven handguns, more than 92,000 rounds of ammunition, a rocket-launcher and two rockets, four mortar shells and two crossbows, the defense department said.

Also seized were a vehicle, holsters, ammunition belts and military uniforms.

Actions such as the seizure of the arsenal in Coahuila, which borders Texas, contribute to the "systematic weakening of the criminal organizations, undermining their operational capacity," the defense department said.

A conflict pitting rival drug cartels against each other and the Mexican security forces has claimed some 40,000 lives since December 2006, when newly inaugurated President Felipe Calderon gave the military the leading role in battling organized crime.

Most of the high-powered weapons used by Mexico's cartels are purchased in the United States, authorities here say.