After bombarding South Korea's female president with sexist invectives, North Korea's state news agency has fired off racist insults against President Barack Obama that U.S. officials condemn as "disgusting."

North Korea is notorious for inflammatory, warlike rhetoric against its rivals South Korea and the U.S. but had rarely used racial slurs in its verbal attacks. Pyongyang's tone has grown angrier in recent weeks as it threatens to conduct a fourth nuclear test.

In a lengthy May 2 dispatch released only in Korean, Pyongyang's Korean Central News Agency published comments from a factory worker who said Obama has the "shape of a monkey" and made many other crude insults.

"It would be better for him to live with other monkeys at a wild animal park in Africa ... and licking bread crumbs thrown by onlookers," worker Kang Hyok at Chollima Steel Complex was quoted as saying. (AP)