US talk show host Rush Limbaugh has come under fire for airing a racially charged song about the Democratic presidential candidate Barack Obama.
Limbaugh has referred to Barack Obama as "Halfrican American"
Limbaugh has been playing a song called Barack the Magic Negro, to the tune of Puff the Magic Dragon.
The right-wing talk show host defended himself by saying he is an entertainer and the song is a parody.
Mr Obama, who hopes to become the first black American president, has played down the row.
Rush Limbaugh, whose radio show is one of the most popular in the US, justified running the song by saying that an article by a black commentator in the liberal Los Angeles Times was the first to link the term "magic negro" to Mr Obama.
Limbaugh said liberals upset about the term should be aware that "magic negro" is a historical cultural term, a reference to benevolent African-Americans portrayed in old films.
The song, he said, was intended to make fun of the problems Mr Obama's candidacy poses to "race-obsessed Democrats", as well as questions from media pundits as to whether Mr Obama was "black enough".
Mr Obama said he had not heard the song but that he did not take himself so seriously as to be offended by every comment made about him.
His campaign team described the song as dumb.
Karl Frisch, a spokesman for Media Matters, a US monitoring group, said the song was consistent with previous comments by Limbaugh, such as referring to Mr Obama as "Halfrican American".
Mr Frisch accused Limbaugh of inflaming his audience.
The song was first aired in March and there has been a lot of internet traffic associated with it.
The CBS News website has temporarily blocked all readers' comments on its stories about Mr Obama.
Mike Sims, the director of the website, said CBS could not collectively delete the derogatory remarks because of their "volume and persistence".
Mr Obama was last week given secret service protection after threats appeared on white supremacist websites.