PRESIDENT Frederik de Klerk is facing a crisis of credibility over his government's clandestine political funding of the Inkatha Freedom Party and reports that special defense force units were involved in civilian massacres.The disclosures point to a bitter power struggle within the government between those who want to promote an anti-African National Congress political alliance through covert means and those committed to an eventual alliance with a moderate and strong ANC. "There is clearly a major tug of war going on within government," says liberal Democratic Party legislator Jacobus Jordaan, an Afrikaner who quit the government three years ago after his security clearance was withdrawn following meetings with the then-outlawed ANC. "The longer black-on-black violence continues, the more it will bolster the cause of those bent on destroying a negotiated settlement," says Mr. Jordaan. "De Klerk needs to come clean. His credibility is being questioned, and his hand at negotiations is being weakened." The disclosures - made simultaneously Friday in two South African and two British newspapers - have created concern in political and diplomatic circles of further delays in negotiations and renewed conflict between the ANC and the Inkatha Freedom Party led by Chief Mangosuthu Buthelezi. They have also severely marred the image of Inkatha and Chief Buthelezi. "Inkatha has been wounded, perhaps mortally, unless it can remove the taint," the Johannesburg Sunday Times said yesterday in an editorial. "Chief Buthelezi will not easily shake off the accusation that he has been reduced to a government stooge," said the newspaper, which is usually supportive of Inkatha. The Sunday Times warned that President De Klerk's "personal reputation cannot endure much more battering. As [ANC President Nelson] Mandela grows in stature, De Klerk is in danger of being dragged down by the sinister forces that lurk in his government." In addition to the US$90,000 Pretoria gave Inkatha for political rallies, Jordaan says he knew of at least US$1.8 million the security police gave Inkatha's trade union wing, the Union of Workers of South Africa. "The disclosures published this week are just the tip of the iceberg," he says. Jordaan says at least a quarter of the government's annual defense budget of US$3.5 billion was spent on secret projects not publicly accounted for in the annual budget. Before leaving for Spain and the Caribbean Friday, Mr. Mandela said the disclosures had set the government and the ANC on a collision course and could lead negotiations to break down. He said that they vindicated the ANC's position that the security forces were working hand-in-hand with Inkatha to destroy the ANC by violent and other means. The disclosures have also lent further credibility to former defense force officer Nico Basson's claims that the force had deliberately provoked township violence to weaken the ANC and help launch an anti-ANC alliance that would keep De Klerk in power after apartheid was dismantled. Three senior government officials have admitted that the government gave secret funds to Inkatha after the ANC was legalized in February last year and its leader, Mandela, was freed. Law and Order Minister Adriaan Vlok admitted Friday the government had made the payments to Inkatha, but he claimed the motive was to counter violence and the international sanctions campaign against South Africa. "Due to the special circumstances applicable in South Africa before February 1990, it was essential to launch covert projects in order to promote order and stability and to counter South Africa's isolation," Mr. Vlok said. Foreign Minister Roelof Botha told the Sunday Times he had authorized the payment of the US$90,000 to fund "anti-sanctions" rallies by Inkatha. He claimed the money was nonpolitical and came from a slush fund earmarked for countering economic sanctions and South Africa's international isolation. Saturday at Inkatha's annual conference in Natal Province, Constitutional Development Minister Gerrit Viljoen defended the payments, saying they were insignificant compared to the funds the ANC had received from foreign organizations and governments. He praised Inkatha for its anti-sanctions stance and said the row should not be allowed to delay the negotiations process. De Klerk said Friday he had halted "numerous covert actions" in mid-1990 and had brought remaining secret projects under Cabinet control. "I believe covert actions should be limited to an absolutely essential minimum." He said it was not government policy to give "direct or indirect financial - or other - support" to any political party. Leaked security-policy documents published Friday in the Weekly Mail, an anti-apartheid weekly, and The Guardian of London refute official claims the funds were not for political purposes. The documents detail plans to support a major Inkatha rally in Durban in March 1990 and elicit money from security police headquarters in Pretoria. In one document, a Maj. Louis Botha of the security police makes it clear the money was needed to counter the ANC's inroads into Inkatha's support-base. The documents say Buthelezi had discussed the political implications of the ANC's erosion of support with the major. Buthelezi said Friday he didn't know of the payments, despite a security police memorandum recording his "gratitude and great appreciation" for the money. For the past six months, Jordaan has been asking in Parliament for De Klerk, Vlok, and Defense Minister General Magnus Malan to state whether the government was funding Inkatha's political campaigns and rallies. All three have evaded the questions, citing "national interest." But outside Parliament, officials have repeatedly denied allegations the state has been secretly funding Inkatha or that a "third force" was at work within the government. On Friday, Pretoria named a senior police officer to investigate reports in The Independent of London and the anti-apartheid weekly New Nation that members of a special defense unit had massacred civilians on a Soweto train in September last year.