A dump truck carrying 36 migrants in a secret compartment was found in Texas near the Mexican border last week, a report said.

Police in Laredo received an anonymous call last Thursday, and the tipster claimed people were trapped inside of a disabled truck that had recently been towed to an impound lot, according to CNN.

When authorities arrived, they heard banging coming from inside the truck, Laredo Police spokesman Officer Emanuel Diaz told the outlet.

The migrants were found in a nook concealed by plywood and covered with a mixture of sand, gravel and dirt.

US Customs and Border Patrol’s South Texas sector, who were dispatched to the scene, said in a Twitter post that the migrants were trapped “with no means of escape.”

The sector also tweeted photos of the truck and the migrants found inside of it.

The agency’s acting commissioner, Mark Morgan, tweeted: “Make no mistake – the criminal organizations and cartels have no concern for the well being of the people they smuggle across the border.”

Those trapped are now in the custody of Homeland Security, according to CNN.