US presidential hopeful Barack Obama has criticised Ludacris after the rapper released a song attacking the Democratic senator's opponents.
A track entitled Politics As Usual, included on the Gangsta Grillz: The Preview mixtape, Ludacris says Republican John McCain does not belong in "any chair unless he's paralysed".
He describes president George Bush as "mentally handicapped" before using a misogynistic term to describe Hillary Clinton, Mr Obama's former opponent for the Democratic candidacy.
The rapper and actor - real name Chris Bridges - also uses the song to advise Mr Obama against selecting Ms Clinton as his running mate for the White House, saying that she "hated on you".
A spokesman for the Obama campaign team has since come out in opposition to the "outrageously offensive" song and criticised the artist who Mr Obama had described in a Rolling Stone interview as part of a group of "great talents and great businessmen" in US hip-hop.
"As Barack Obama has said many, many times in the past, rap lyrics today too often perpetuate misogyny, materialism, and degrading images that he doesn't want his daughters or any children exposed to," campaign spokesman Bill Burton was quoted by the Associated Press news agency as saying.
"This song is not only outrageously offensive to Senator Clinton, Reverend Jackson, Senator McCain and President Bush, it is offensive to all of us who are trying to raise our children with the values we hold dear.
"While Ludacris is a talented individual he should be ashamed of these lyrics."