Tijuana Tunnel

A soldier of the Mexican Army walks along a trans-border tunnel found near Tijuana Airport, in Tijuana, in the Mexican border with San Diego in the US, on August 11.

Mexican troops have discovered an unfinished 980-foot tunnel beneath the U.S. border that that officials say would likely have been used to smuggle drugs and people, AFP reports.

Mexican General Alfonso Duarte announced the find on Friday, saying the entrance to the tunnel was inside a house in the border town of Tijuana that was made to appear as though it was under construction.

He added that 10 people were detained in the operation, including a woman who had been helping to dig the tunnel for nearly a year.

The tunnel was around six feet high and three feet wide, and had a lighting and ventilation system, officials said.

U.S. officials said in June that more than 150 secret tunnels for smuggling people and drugs into the United States have been found since 1990.