South African president Jacob Zuma was given a red-carpet welcome in Tripoli after flying in to try to broker a peace deal withLibyan leader Colonel Muammar al-Gaddafi.
He arrived just hours after Nato's secretary-general said the Libyan leader's "reign of terror" was coming to an end.
Mr Zuma was met by a host of dignitaries, but not Col Gaddafi, who has not been seen since 11 May, when he appeared on Libyan state television meeting tribal leaders.
The South African president's walk down the red carpet at Tripoli airport was accompanied by a band and children chanting "We want Gaddafi" in English while waving Libyan flags and pictures of the leader.
It is Mr Zuma's second visit since the conflict began - his first failed to make progress because Col Gaddafi refused to relinquish power, which rebel leaders said was a pre-condition for any truce.
Nato warplanes have been raising the pace of their air strikes on Tripoli, with Col Gaddafi's Bab al-Aziziyah compound in the centre of the city being hit repeatedly.
Journalists escorted into Bab al-Aziziyah after Mr Zuma's arrival found a group of about 160 African visitors chanting pro-Gaddafi slogans and waving flags of nations including Chad, Niger and Ghana, in an apparent show of pan-African unity.
The UK has warned it will add "bunker-busting" bombs to the arsenal its warplanes are using over Libya.
Nato secretary-general Anders Fogh Rasmussen said: "Our operation in Libya is achieving its objectives. We have seriously degraded Gaddafi's ability to kill his own people.
"Gaddafi's reign of terror is coming to an end. He is increasingly isolated at home and abroad. "Even those closest to him are departing, defecting or deserting."
The Libyan leader has denied attacking civilians, arguing his forces are actually trying to contain armed criminal gangs and al-Qaeda militants.
He has said the Nato intervention is an act of colonial aggression aimed at grabbing Libya's plentiful oil reserves.
Meanwhile, US Admiral Samuel Locklear, commander of the Joint Operations Command at Naples, declined to comment on whether Nato would put forces on the ground but suggested a small force may be needed to help the rebels once Col Gaddafi's rule collapses.
He told a Nato forum in Varna, Bulgaria: "I would anticipate that there might be a need at some point to unfold a small force - a small number of people there to help them in some way."The military alliance says it is acting under a mandate from the United Nations to protect civilians from attack by security forces trying to put down the rebellion against Col Gaddafi.
But the more aggressive tactics risk causing divisions within the fragile alliance backing the intervention, and could also lead to Nato being dragged closer towards putting its troops on Libyan soil.