U.S. authorities say they have discovered a drug tunnel between Mexico and California, the second such tunnel found in less than two weeks.

A spokeswoman for U.S. Immigration and Customs Enforcement said Tuesday the tunnel opened into a California warehouse located in the same San Diego neighborhood as the previous find. The spokeswoman did not give any other details.

On Monday, a Mexican trucker was sentenced to nearly 16 years in a U.S. prison for his role in smuggling drugs through two similar passageways discovered last year.

Raids on those two tunnels netted a combined 50 tons of marijuana on both sides of the border. They were equipped with rail systems, lighting and ventilation. The tunnels are among dozens that have been discovered in recent years.

Mexico is in the midst of brutal drug gang violence that has claimed an estimated 45,000 lives since President Felipe Calderon took office in late 2006 and began a crackdown on the cartels.