U.S. Customs officials seized a package stuffed with small, dead birds in a passenger's luggage at Dulles International Airport in the Washington, D.C. area, officials announced Monday.

U.S. Customs and Border Protection (CBP) said that the passenger arrived at the airport from Beijing, China. The person's final destination was supposedly a residence in Prince George's County, Maryland.

During a security check, Customs specialists found a package filled with a bunch of unknown small birds, about 2.5 to 3.5 inches in length. The package was decorated with pictures of cats and dogs.

The traveler told authorities that the bird bodies were "cat food."

The birds were then seized on behalf of the U.S. Department of Agriculture and destroyed by incineration.

It's illegal to import birds from China due to the threat of highly pathogenic avian influenza.

“These dead birds are prohibited from importation to the United States as unprocessed birds pose a potentially significant disease threat to our nation’s poultry industries and more alarmingly to our citizens as potential vectors of avian influenza,” said Casey Durst, Director of Field Operations for CBP’s Baltimore Field Office in a

“Customs and Border Protection agriculture specialists continue to exercise extraordinary vigilance every day in their fight to protect our nation’s agricultural and economic prosperity from invasive pests and animal diseases," according to Durst.