U.S. Customs and Border Protection officials seized more than 1,650 pounds of marijuana at the Blue Water Bridge in Port Huron over two weeks in August, the agency announced Tuesday.

On Aug. 28, a tractor trailer carrying bulk mail was flagged for secondary inspection, according to an agency press release. A K-9 officer alerted "multiple packages" in the shipment, leading to the discovery of some 14 packages containing 300 pounds of pot.

Over the next 10 days, customs officials, aided by Homeland Security and the St. Clair County Sheriff's Office, discovered 63 more packages containing more than 1,300 pounds of marijuana.

The drugs, which are illegal in America under federal law, will be destroyed. The Canadian drivers were released, along with their trucks. Authorities said they were not involved and were unaware they were carrying the drugs.

No suspects have been identified at this time, the agency said.