FILE PHOTO: Pigs are seen in a piggery at a village near Warsaw April 10, 2014. REUTERS/Kacper Pempel/File Photo

CHICAGO (Reuters) - The United States has lifted restrictions on some imports of fresh and frozen pork from Poland, specifically from facilities that are in contiguous areas free of the highly contagious hog disease African swine fever, the U.S. Department of Agriculture said Thursday.

The ban remains in place on imports of raw and heat-treated pork products that are not fully cooked, as USDA officials review Poland’s export protocols, the agency said.

Last week, the United States suspended all imports of pork from Poland over concerns of the potential spread of African swine fever, which has spread rapidly in eastern Europe and China.

The United States is free of the disease, and anxious to keep it that way because infections in U.S. herds would likely kill hogs and limit pork exports. Humans are not susceptible to African swine fever, according to USDA.