We must deal with the abandonment of progressive ideas of some of the leadership of the Democratic Party

Al Sharpton

Mr Sharpton said that he wanted to halt the Democratic Party's drift to the political right.

He has formed an exploratory committee prior to launching a bid for the Democratic nomination for the next US presidential elections.

The committee is to be headed by the prominent Harvard academic, Professor Cornel West, who supported Green Party candidate Ralph Nader in the 2000 election.

Well ahead

Its job will be to determine the scope for a Sharpton bid for the presidency - how much support he can attract from other black leaders, how easy would it be to raise money to fund a campaign, and so on.

The BBC's Jonathan Marcus says that in getting in well ahead of the field, Mr Sharpton is putting down a marker.

He told the BBC that his principal focus was the need to reform the Democratic Party itself.

Sharpton has been trying to make up weight lost in prison

"I think that we must deal with the abandonment of progressive ideas of some of the leadership of the Democratic Party and the need to force this party to clarify its position on things like public education, the criminal justice system and international policy," he said.

Correspondents say that Mr Sharpton has little or no chance of actually winning the Democratic nomination, let alone the presidency.

But our correspondent says that the civil rights activist clearly hopes to emerge as a key power broker to influence the party's agenda and to have an important say over who becomes its standard bearer in the next presidential race.

Sharpton is a founder of a civil rights organization called National Action Network.

He made two unsuccessful bids for the US Senate in 1992 and 1994 and ran for New York mayor in 1997 but lost.