MEXICO CITY (Reuters) - Mexico will ban all imports of poultry and poultry products from Arkansas after a small flock in that U.S. state had been exposed to a mild form of bird flu, the agriculture ministry said on Wednesday.

Mexico, whose largest trading partner is the United States, joined Japan, Russia and Taiwan who also closed their borders temporarily to chicken imports.

Mexico said it would resume imports once the virus was completely contained. U.S. chicken from other states still can be shipped to Mexico.

"U.S. and Mexican technicians are investigating the case and analyzing the risk. Once the outbreak is controlled and sanitary conditions are back to normal, commercial activity will resume," the ministry said in a statement.

Mexico consumes more poultry than it produces, importing the rest. But it imports less than Russia, the largest export market for U.S. chicken.

Tyson Foods Inc, the largest U.S. meat company and No. 2 chicken producer, said this month it was destroying about 15,000 chickens in an Arkansas flock that had been exposed to a mild strain of bird flu.

(Reporting by Mica Rosenberg and Adriana Barrera; Editing by David Gregorio)