NOGALES, Ariz — U.S. Border Patrol agents, with help from Mexican authorities, discovered another smuggling tunnel in Nogales this week.

The department says the incomplete tunnel was discovered in a Mexican drainage system about 580 yards from the border and says it was dug by cartel members.

Three border tunnels were discovered in Nogales last year along with hundreds of pounds of illicit drugs like meth, cocaine and fentanyl in one instance. Border agents also say such tunnels are connected to human trafficking.

The tunnel discovered Tuesday was the 126th found in the Tucson Sector since 1990.

Border agents will monitor the area until the tunnel is sealed.

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- Look inside a drug tunnel that Border Patrol agents are training to detect