After a hectic day spent getting a glimpse of daily life in Ghana, U2 singer Bono and U.S. Treasury Secretary Paul O'Neill flew Thursday to South Africa on the second-leg of their four-nation African tour.

They were due to arrive in Pretoria in mid-afternoon and head straight into meetings with South African President Thabo Mbeki, the finance minister and the central bank governor.

Their 10-day trip through four Sub-Saharan countries has been billed as a fact-finding mission by the Treasury, and as an exercise in persuasion by the Irish pop legend.

Bono is determined to show the sometimes skeptical Republican that aid can be put to good use on the problem-plagued continent.

In South Africa, the men will visit an AIDS research clinic, a housing project and a Soweto high school. They will also tour the Johannesburg stock exchange.

The treasury secretary and the lead singer of the Irish band U2 will be in South Africa until Sunday when they fly to Uganda. After two days there, they continue to Ethiopia.

On Wednesday, Bono and O'Neill toured a market in Ghana's capital, Accra. They met children in spotless yellow-and-brown uniforms at a vocational school, and flew to the northern town of Tamale to speak to local chiefs in a nearby rural village.

Throughout the two days in Ghana, Bono has repeatedly argued that Africa still desperately needs more aid to construct basic infrastructure like clean water and proper roads.

O'Neill has been a vocal critic of anti-poverty programs, saying they wasted billions of dollars because they failed to generate real economic development. He has stressed the role of private enterprise in spurring development on the continent.

"Believe me, I'm not rushing back to where we've been because that has not worked. One thing I've said again and again is results, results, results," he told reporters.

A violent storm delayed their return to Accra Wednesday, leaving them stranded for six hours at Tamale airport before the speedy Ghanaian presidential jet was sent from Accra to ferry the group back to the capital in record time.

The African trip comes after a new U.S. commitment to boost aid by dlrs 10 billion in 2004-06 through the Millennium Challenge Accounts.

The idea for the joint tour was hatched a year ago, when the two men met in O'Neill's office. Initially reluctant to meet, O'Neill later said he was impressed by the singer's knowledge about Africa.