CLAUDINE LoMONACO

Border Patrols agents discovered a recently dug tunnel that crossed the border and ended under downtown Nogales, Ariz.

Agents found the tunnel Thursday after arresting several illegal immigrants who agents believed came through the tunnel, according to a statement released by the U.S. Border Patrol.

Agents overheard voices coming from a nearby ground-level steel grate while patrolling the area near West Street and Interstate 19. Agents removed the grate and entered a drainage system, causing several men to flee south through the tunnel toward Mexico.

The tunnel was dug to get around security obstacles placed in the drainage system, the statement said. It crossed the grate and appeared to head north across Interstate 19.