PHILADELPHIA (CBS) -- Federal authorities in Philadelphia seized about 300 leeches from Bulgaria in air cargo shipments. U.S. Customs and Border Protection said Wednesday officers recently intercepted nine jars postmarked for addresses in Connecticut, Florida and Illinois between Feb. 19 and Feb. 25.

Authorities said the jars contained about 300 of the bloodsuckers. Labels on the jars claimed the leeches were Hirudo Orientalis, but a U.S. Fish and Wildlife Service inspector confirmed they were Hirudo Medicinalis, a species that is used in medical bloodletting treatments.

The shipments violated the U.S. Endangered Species Act, authorities said. The law prohibits the "unlicensed possession, trade, import and export of protected species of wildlife or wildlife products."

"Customs and Border Protection officers and agriculture specialists often encounter unique and interesting things, like this jar full of icky bloodsuckers, while inspecting goods being imported to the United States," CBP Philadelphia Area Port Director Joseph Martella said. "CBP officers remain committed to collaborating with federal, state and local law enforcement partners to intercept shipments that violate our nation's laws and potentially threaten harm to our nation's citizens and our economy."

The seizure happened last Thursday.