U.S. Customs and Border Protection (CBP) agents at the Del Rio, Texas, port of entry said they seized a shipment of methamphetamine valued at $11.9 million, making it makes it the largest seizure of this drug at the port of entry.

The drugs were found inside a tractor-trailer, CBP said in a news release Wednesday. He said he made the discovery Monday after a CBP Office of Field Operations agent referred the truck carrying a shipment of diesel tanker containers for a secondary inspection.

A non-intrusive canine inspection uncovered 320 packages containing 1,337 pounds of suspected methamphetamine, CBP said.

“This is a massive methamphetamine seizure, the largest in the port’s history, and reflects our agents’ steadfast commitment to CBP’s border security mission and their effective application of technology, training and expertise,” he said in a statement. the director of the port of entry, Liliana Flores.

Special agents from US Immigration and Customs Enforcement are investigating the seizure, CBP said.