Rapper Nas is calling for bosses at U.S. TV network Fox to end their "pattern of racist attacks against Black Americans" by delivering a 600,000-name petition at the media giants' New York headquarters.

The outspoken hip-hop hero will join ColorOfChange.org and MoveOn.org activists in a protest outside Fox's Manhattan offices on Wednesday.

Nas has been a long-time critic of the channel, and takes aim at conservative news broadcasters in his new song Sly Fox.

Nas is particularly upset at Fox broadcasters' subtle jabs at African-American presidential hopeful Barack Obama.

The rapper says, "Fox poisons the country with racist propaganda and tries to call it news."