Tens of thousands of African-Americans have been taking part in a rally in Washington to mark the 10th anniversary of the Million Man March.
Farrakhan wants to charge the government with "criminal neglect"
Many of the crowd voiced their anger at what they perceive as the unequal treatment of black people in the US.
Speakers said this was highlighted by the fate of poor black communities following Hurricane Katrina.
Correspondents say the number attending the rally appears to be down on the original march in 1995.
Neither the police nor the organisers gave an estimate for the size of the crowd.
The leader of the Nation of Islam movement, Louis Farrakhan, told the audience the federal government was guilty of failing to react more quickly to the disaster.
"I firmly believe if the people on those rooftops had blond hair and blue eyes and pale skin, something would have been done in a more timely manner," he said.
"We charge America with criminal neglect."
Veteran civil rights leader Jesse Jackson said African-Americans should channel their frustration and energy into changing their communities.
"Don't imitate the violence, racism, anti-Semitism, anti-Arabism, gay bashing," he said.
"We need... millions more to build a multicultural coalition, we need not battle alone to fight poverty and greed and war."
The day-long event attracted a large number of speakers, including academics, activists and artists.
The original Million Man March was aimed at encouraging black men to improving their families and communities, and drew between 600,000 and one million people.
Mr Farrakhan, a controversial figure who has made anti-Semitic and homophobic statements in the past, did not repeat recent allegations that the New Orleans levees might have been blow up by a bomb in a deliberate attack on New Orleans.