Mexican soldiers have discovered a so-called "narco-tunnel" in Baja California that extends under the U.S. border, Mexican military officials said Friday.
The unfinished tunnel is 298 meters (977 feet) long, two meters (6.5 feet) high and about half that wide, and is thought to be intended for smuggling drugs, the National Defense Secretariat said.
Ten people, including one woman, were arrested as they were excavating, the agency said. Tools were also confiscated from the site.
The tunnel, which started inside a house and has lighting and ventilation, is thought to have started a year ago. Mexican military personnel came across it around 6 a.m. Friday, said Gen. Alfonso Duarte.