MIAMI (AP) — U.S. Customs and Border Protection agents have seized a shipment of marijuana worth an estimated $4 million at Miami’s seaport.

Authorities said Tuesday more than two tons of marijuana was intercepted in a shipping container from South America. The pot was in 40 bags inside the container.

CBP says agents became suspicious about the container because it appeared to have been tampered with. Drug-sniffing dogs were brought in and alerted to the presence of drugs. Lab testing confirmed the substance was marijuana.

CBP Miami Field Operations Director Vernon Foret says it’s the agency’s single largest marijuana discovery at the port. Foret says CBP has intercepted about 3,800 pounds on several previous occasions.

No arrests have been made.

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