Feb. 27 (UPI) -- U.S. Border Patrol agents have discovered another illegal cross-border tunnel with Mexico, United States Customs and Border Protection said Thursday.
The unfinished, hand-dug tunnel runs beneath the streets of Nogales, Ariz., and is the third to be discovered in the Tucson Sector since December, according to information from CBP.
Agents with the Tuscon Sector and Mexico's Guardia Nacional located the tunnel's entrance Tuesday in the floor of Grand Avenue drainage system in Mexico, CBP said in a press release.
The tunnel runs approximately 15 to 20 feet underground and is around 30 feet long but was left uncompleted about 580 yards west of the Dennis DeConcin Crossing at the Nogales Port of Entry.
"U.S. Authorities will continuously monitor the area until they remediate the tunnel," CBP said in a statement.
It is the 126th tunnel discovered in the Tucson Sector since 1990, it said.
"U.S. Border Patrol regularly works with the government of Mexico, and binational cooperation with Mexican law enforcement plays a vital role in border security," CBP said. "Efforts such as tunnel sweeps aim to disrupt smuggling organizations and prevent the smuggling of narcotics and humans across the border."
News of the tunnel follows agents discovering the longest-ever cross-border tunnel in the San Diego Sector of California at 4,309 feet, more than three-quarters of a mile.