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.
Marie Harf, a State Department spokeswoman, said Thursday that the North Korean dispatch was "offensive and ridiculous and absurd."
"I don't know how many words I can use up here to describe the rhetoric ... It's disgusting," she told reporters at the Foreign Press Center in Washington.
Yoo Ho-yeol, professor of North Korea studies at Korea University in South Korea, said North Korea is trying to get attention by publishing such comments through its state-run news agency. But he added that it tried to distance the government from the remarks by attributing them to a citizen.
"If it was to publish such a report in the voice of the authorities it would entrap them, whereas reporting the story under some ordinary citizen's name will give them leeway," Yoo said.
The North's rhetoric against Obama and South Korean President Park Geun-hye intensified after they held a summit in Seoul late last month. During his visit, Obama said at a joint news conference with Park that it may be time to consider further sanctions against North Korea, and that the U.S. will not hesitate to use its military might to defend its allies.
Recent state media dispatches criticizing Park are full of sexist tirades such as "old prostitute coquetting with outside force."
Associated Press writer Jung-yoon Choi contributed to this report.