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.

Mexico has seen a wave of unrest in recent years as powerful drug cartels have battled over lucrative trade routes to the United States, with some 41,000 people killed in drug-related violence since 2006.

That year President Felipe Calderon launched a massive military crackdown, which critics say has led the cartels to develop more advanced tactics and more brutal methods without bringing security to border communities.