LOS ANGELES, CA (Catholic Online) - The tunnel was found last week after authorities received an anonymous call in the border city of Nogales, Sonora, south of Arizona. U.S. law enforcement confirmed that the Mexican military had discovered the football field-long tunnel. According to U.S. Border Patrol spokesman Victor Brabble, the tunnel did not cross into the U.S.

The anonymous caller said they saw gunmen standing outside a two-story house in a hilly neighborhood near the international bridge, where travelers cross into Mexico and the United States.

Soldiers discovered a fake wall inside the home. A storage closet was discovered under a staircase that led to a dark room with buckets and clothes. After lifting a drain cover in that room, soldiers found another staircase at the entrance of the tunnel that went 16 feet underground and measured a yard in diameter.

Officials found that light bulbs dotted the underground passage, with pipes stretching across the 120-yard tunnel. Mexican army officials believe was built to smuggle drugs.

It's not yet known if officials have made any arrests, but the house where the tunnel was found was seized by the local government. Officials didn't say how long they believed the tunnel had been under construction. It's believed that construction time for such a passage is six months to a year.

Sophisticated secret tunnels stretching across the international border have become increasingly common as drug cartels invent new ways to smuggle enormous loads of heroin, marijuana and other drugs into U.S.

More than 70 such tunnels have been found since October 2008, most of them concentrated along the border in California and Arizona. In Nogales, Arizona, smugglers tap into vast underground drainage canals.

© 2012, Distributed by NEWS CONSORTIUM.