President F.W. de Klerk will meet President Bush on Sept. 24 in the first U.S. visit by a South African leader in decades, a government official said today. De Klerk, who has launched wide-ranging reforms since assuming power a year ago, was scheduled to meet Bush in June. But the visit was canceled after anti-apartheid groups in the United States protested, saying Bush should first hold talks with African National Congress leader Nelson Mandela. Mandela, who saw Bush in June, said it did not matter who met first with the U.S. president. Mandela has said his movement has no objections to a Bush-de Klerk meeting, but wants to United States to maintain its limited economic sanctions against South Africa to protest apartheid. A South African government source, who spoke on condition of anonymity, said an official announcement of de Klerk's visit would be made this afternoon. No South African leader has visited the United States since the apartheid system of racial segregation was formally implemented in the late 1940s, officials said. De Klerk says he wants to end apartheid and negotiate a new constitution with opposition groups that would allow whites and blacks to share power. Under apartheid, the 5 million whites dominate politics and the economy and the 30 million blacks have no voice in national affairs.