EDINBURG, Texas (ValleyCentral) — U.S. Border Patrol agents from the Rio Grande Valley Sector reported six large groups of non-citizens and the disruption of a human smuggling attempt at the checkpoint.

According to the agency, agents at the Falfurrias Border Patrol checkpoint rescued 13 migrants from a locked tractor-trailer on Tuesday.

After a K-9 alerted agents, they said they referred the rig for a secondary inspection. The subjects were discovered hidden among pallets of scrap metal.

In addition, three non-citizens were found hidden in the cab of the truck. Those arrested are from Mexico, El Salvador, Guatemala, and Brazil.

In the last three days, McAllen Border Patrol Station agents encountered four large groups near Mission and Hidalgo.

The groups were made up of 176 single adults, 190 family members, and 101 unaccompanied children. They are from various Central and South American countries, and Cuba.

CBP added that Rio Grande City Border Patrol Station agents encountered two other large groups near La Grulla. The groups were comprised of 119 single adults, 145 family members, and 82 unaccompanied children from Cuba and Central American countries.