In his first speech in Tripoli since Col Gaddafi was ousted from the capital, Mahmoud Jibril said "our biggest challenge is still ahead".

He refused to discuss the whereabouts of Col Gaddafi, who earlier dismissed reports that he had fled to Niger. Meanwhile, hundreds of black Africans were fleeing Libya daily, the UN said.

The International Organization for Migration (IOM) said up to 300 black Africans were crossing into Niger every day because they were being systematically targeted by the forces of the National Transitional Council (NTC).

It seems that that all black Africans in Tripoli are accused of having backed Col Gaddafi as some of them were used as mercenaries to defend his regime.

Mr Jibril warned that Gaddafi loyalists still controlled several cities, adding that Libya's liberation would only end with the "capture or elimination of Gaddafi".

The NTC has been trying to negotiate a peaceful resolution to stand-offs in a handful of Libyan towns or cities still controlled by Gaddafi loyalists.

The International Criminal Court (ICC) is seeking the arrest of Col Gaddafi, his son Saif al-Islam and his former intelligence chief Abdullah Sanussi for alleged crimes against humanity.