PRETORIA, SOUTH AFRICA — THE failure of a national peace accord to halt political violence in South Africa has not shaken the government's commitment to a nego- tiated political solution, President Frederik de Klerk said in an interview yesterday.Mr. De Klerk said that his faith in the vision of a new and democratic South Africa is intact. "The fact is that I am absolutely committed," De Klerk said resolutely. "The mere fact that I am continuing to do what I am doing - despite the tremendous resistance - is proof of that commitment." Although there is growing concern among South African businessmen and international investors at the levels of violence in the country, De Klerk appeared certain that the initiative he has begun will bring peace and economic prosperity to a post- apartheid South Africa. De Klerk said he was confident that all-party talks on drafting a new constitution would be held before the end of the year, and that the convening of such a conference presented the best chance of ending violence. "We are sorry that the peace accord has not had more impact than it has [on political violence], but everyone at the peace convention indicated that they did not expect the violence to just stop because [of the] the signing," he said. De Klerk was referring to the September signing of the National Peace Accord, which created mechanisms to give black South Africans a say in the management of the country's security forces. "I am doing everything in my power to ensure that we act against the violence in a democratic way," he said, adding that only a commitment to negotiations could end the violence. "The biggest single contribution toward bringing the black-on-black violence to an end would be for the leaders to sit together in a multiparty or all-party conference," he said. "That is on the cards," De Klerk said, citing an anti-apartheid unity conference which ended in Durban Sunday with the two major liberation movements - the African National Congress (ANC) and the Pan Africanist Congress (PAC). The delegates agreed for the first time on a call for all-party negotiations. The conference closed the gap between the two main liberation movements and advanced the timetable for full political negotiations. De Klerk welcomed the turnaround by the PAC, which has strenuously resisted talks with the government. "It succeeded in drawing the PAC into a negotiating commitment and in that sense it had a positive effect," De Klerk said. He said it was an important conference which represented the views of a significant section of the country, but he expressed reservations about some of the positions adopted. "The wording of the declaration leads one to get the impression that it is unwise to line yourself, in a specific manner, to too rigid points of view. This could undermine the flexibility one would like to see at the negotiating table." De Klerk also said his government was going to great lengths to ensure effective policing and had expanded the force by 10,000 in the space of a year. He was convinced of police impartiality in the majority of cases, he asserted, and vowed that the government would act against individuals who violated the law. "Governments have the problem across the world that the members of their forces are not always exactly in line with government policy, but I don't think it is more serious here now than in other countries." He said the newly appointed judicial commission on the prevention of violence provided an "objective mechanism" to adjudicate on claims of police partiality. On political issues, he said he was prepared to negotiate the relinquishing of some power and the creation of an interim authority during the transition period away from apartheid, but insisted that this would have to be preceded by constitutional amendments and a national referendum. De Klerk called on ANC President Nelson Mandela to give a clear lead and to say what he really feels. "The ANC is blowing hot and cold. One day they come across as really conciliatory.... The next day they make the most outrageous demands and threats." "Mr. Mandela must give the kind of leadership that will cost him some of his support," said De Klerk, describing the ANC as being an uneasy alliance with the South African Communist Party. De Klerk ruled out a sovereign interim government, saying it meant "suspending the Constitution and ruling in a vacuum by decree." The other alternative was to create "transitional mechanisms similar to the National Peace Accord - which would give those excluded from Parliament a say in government without undermining the government's authority. They would not require amending the Constitution or holding a referendum, he said. The president appeared to distance himself slightly from his ruling National Party's controversial constitutional proposals - which would give minorities an effective veto power in an upper house - by insisting they should be accepted by their critics at least as "a chapter in a phased process." He said an economic recovery was being frustrated by the ongoing violence and what he called "outrageous" economic demands by the ANC, such as its recent calls for nationalization and threatening to renege on foreign loans entered into by the present government. He said he would not allow the creation of a government that propagated such views or that did not fully honor private property ownership. "That's my bottomline," he said. "I will not say 'yes' to a system that undermines private property ownership." De Klerk said he was sorry - and had said so - about the negative effects of apartheid, but he did not believe that a "Nuremberg" approach would bring restitution and reconciliation. "I think one should accept the painful parts of history with a sense of sorrow and learn from that and not make the same mistakes in the future."