WASHINGTON (Reuters) - Russia has banned U.S. pork imports from two Tyson Fresh Meats (TSN.N: Quote, Profile, Research) plants and two Farmland Foods plants as of May 5, the U.S. Department of Agriculture said late Monday.

The banned Tyson plants are located in Storm Lake, Iowa, and Logansport, Indiana, and the Farmland plants are in Crete, Nebraska, and Monmouth, Illinois.

The USDA did not state the reason for the ban.

(Reporting by Ayesha Rascoe; Editing by Marguerita Choy)