PHOENIX -- An incomplete tunnel between the United States and Mexico was discovered Wednesday, U.S. Customs and Border Protection said in a release.
The 133-foot tunnel was discovered during a border sweep conducted by both American and Mexican authorities.
The tunnel, which had an average height of three feet, was found after authorities found fresh dirt in a drainage system. The tunnel did not have an opening on the United States' side of the border.
Tunnels are often used by drug cartels to smuggle drugs across the border and into Arizona.