JOHANNESBURG, JUNE 7 -- President Frederik W. de Klerk announced today that he will end the four-year-old national state of emergency everywhere but in strife-torn Natal province, a decision that may induce many Western European nations, if not the United States, to begin phasing out sanctions against South Africa.

De Klerk told Parliament in Cape Town that he will not renew the general state of emergency decree, which is due to lapse at midnight Friday.

The president said "the point has now been reached" when "the ordinary laws of the land" could deal with the present level of violence, except in Natal, where factional fighting among Zulus has reached near civil war.

De Klerk said he believed that by ending the state of emergency he had resolved "one of the most important issues constantly raised inside and outside South Africa." During the state of emergency, more than 50,000 blacks have been taken into custody without charge, some for up to three years. Police have had the power to search any building and restrict access to any area deemed a site of civil disorder. The government also has used emergency powers to impose press censorship and ban organizations.

South African black nationalist leader Nelson Mandela, who is on a tour of West European capitals arguing for a continuation of sanctions, said in Paris today that his organization, the African National Congress, is "happy" that the state of emergency had been lifted. "It is a victory for the people of South Africa as a whole, both black and white," he said.

But Mandela questioned whether continuation of the emergency in Natal would help much. "It has been enforced since 1986 and . . . the level of violence has not abated, so it has served no purpose whatsoever," he said.

De Klerk denied that he had taken the step under pressure or to "gain political capital," but he said nonetheless that "the net result of the lifting of the state of emergency is that one of the main stumbling blocks" to the start of constitutional negotiations with South African black leaders had been removed.

He indicated later that he hoped his decision would induce Western nations to end economic and other punitive sanctions against South Africa.

Ending the state of emegency was one of five specific conditions that the U.S. Congress set forth in the 1986 Comprehensive Anti-Apartheid Act for presidential consideration of a lifting of any of the U.S. economic sanctions against South Africa.

{A White House statement welcomed De Klerk's announcement, calling it "another significant step towards creating a climate conducive to negotiation that will lead to a democratic, non-racial, South Africa." The statement called for further steps, specifically resolution of the issue of political prisoners, transformation of the "continuing climate of violence and intimidation" and an end to the killings in Natal.

{The White House said that with the new move, the de Klerk government "has moved to meet almost all the opposition's requirements to enter into negotiations." The statement said the United States looks forward to "the early beginning of a negotiating process."

{The State Department noted that, under the law, U.S. sanctions still could not be lifted. "The conditions laid down in the Comprehensive Anti-Apartheid Act must be met before we can suspend or modify the sanctions," spokesman Richard Boucher said.

{"Specifically now, we'll have to look at the legal implications of continuing the state of emergency in Natal. The law also requires that all political prisoners must be released, and this has not yet happened," Boucher said.}

Congressional and administration sources said recently that they did not expect any action toward lifting of the sanctions until at least after the fall congressional elections.

West European leaders have told de Klerk that an end to the state of emergency would be a major factor in a decision on easing sanctions expected to be taken by foreign ministers of the European Community when they meet in Dublin June 25.

De Klerk also announced today that 48 blacks imprisoned for political offenses were being released as a gesture of goodwill pending resolution of the fate of all political prisoners -- estimated to number between 350 and 3,500 -- in the talks taking place between the ANC and the government on this issue.

In contrast to Mandela's remarks in Paris, ANC officials here offered de Klerk little praise for his decision. "We are not calling for half-measures," said senior ANC leader Water Sisulu. "Clearing the atmosphere for negotiations included the entire lifting of the state of emergency."

The ANC has demanded scrapping of the Internal Security Act, which gives the government sweeping powers to suppress anti-apartheid activities and make arbitrary arrests and unending detentions. De Klerk said the government was reviewing aspects of all security laws that might possibly inhibit peaceful political activity to see if they could be annulled.

De Klerk also criticized the ANC today for postponing until July 10 a statement of its position on various unresolved issues -- including the definition of a political prisoner -- raised in early May in talks aimed at removing the obstacles to formal negotiations for a new constitution.

He said it was time for the ANC to "stop vacillating" and declare unequivocally where it stood on such key issues as ending armed conflict and rejecting violence. De Klerk complained that while Mandela had rejected "all forms of violence" in a June 2 speech, the ANC leader had also declared approval of "organized violence in the form of armed activity which is properly controlled and where the target is carefully selected."

De Klerk cited as the main reason for maintaining the state of emergency in Natal "the increasing phenomenon {there} of violence among blacks, which has led to destruction of human life and property and has assumed shocking proportions."

For this reason, he said, he was including in the emergency area the nominally self-governing Kwazulu tribal homeland. Spiraling warfare between Zulu supporters of Kwazulu's chief minister, Chief Mangosuthu Buthelzei, and other Zulus aligned with the ANC has caused the crisis in Natal.

However, the government has rarely used the restrictive provisions of the emergency law to halt the fighting in Natal. This has led to charges by pro-ANC factions there that police allow the violence to continue in the hope that local ANC leaders will be eliminated by Buthelezei's supporters.

The state of emergency has been in force since June 12, 1986, when de Klerk's predecessor, Pieter W. Botha, imposed the measure to cope with racial turmoil that the government feared would erupt as blacks marked the anniversary that year of the 1976 Soweto township uprising.