Mexican soldiers on patrol in the western state of Sinaloa discovered an elaborate underground laboratory for the manufacture of crystal meth and other synthetic drugs, the defense department said.
The facility is 10 meters (33 feet) deep, 12 meters (39 feet) long and 10 meters wide, the department said in a statement.
One level of the two-story metal structure houses a kitchen and sleeping quarters, while the other consists of two workspaces and a warehouse.
Equipped with an elevator and air conditioning, the site near the town of San Antonio is the most-sophisticated illegal drug lab found so far in Mexico, the defense department said.
Soldiers confiscated 440 kilos (969 pounds) of methamphetamine and substantial quantities of drug precursor chemicals, as well as six organic-synthesis reactors, five condensers, six gas tanks, 11 burners and other gear.
Mexico, which produces most of the crystal meth consumed in the United States, has tightly restricted imports of chemicals used in the production of illegal synthetic drugs, seizing hundreds of tons of precursor chemicals in recent years.