It is Zuma's second visit to Tripoli to try to mediate an end to the fighting that began more than three months ago when Gadhafi dug in his heels against popular efforts to bring about an end to his 42-year-rule.

But unlike many other world leaders, Zuma, his African National Congress party and the African Union, which he will represent on his trip, and which Gadhafi himself once led, have not called for the longtime Libyan leader to step down. In fact, it has criticized the NATO airstrikes targeting government forces.

The NATO-led bombing campaign began in March after the UN Security Council authorized the use of any means necessary, with the exception of occupying Libyan land, to protect civilians from attacks by Gadhafi's forces.

Noureddine Mezni, an African Union spokesman, said Zuma will push for a cease-fire and peace talks between the warring parties. The African Union has helped mediate such talks before, including ones in Kenya and Zimbabwe that left the ruling powers still in control.