The U.S. Border Patrol says a road construction crew has uncovered an abandoned tunnel in Texas, just north of the border with Mexico.

Agent Oscar Cervantes says the tunnel was discovered Thursday near downtown El Paso. It is about 25 yards (23 meters) long. Cervantes said Friday that there’s no indication the tunnel goes into Mexico.

The Border Patrol said in a statement that the Texas Department of Transportation reached out after a cave-in during construction of a road. The mishap led to the discovery of the tunnel that originates north of the international border. Authorities don’t know the purpose of the tunnel.

Border Patrol confined-space resource teams are examining the area to determine the extent of the tunnel, apparently reinforced with wooden beams.

(AP)