JOHANNESBURG — AT the most representative gathering of its kind in three decades, anti-apartheid leaders from some 2,000 organizations vowed Saturday to force President Frederik de Klerk to move beyond the limits he has set on his liberalization program. ``We are aware that De Klerk has no choice but to go further than his predecessors,'' said the white-haired African National Congress (ANC) leader Walter Sisulu. ``But we know that - of his own accord - he has limits beyond which he will not go. It is our historic purpose to take him there, or to go without him.''
But Mr. Sisulu, the keynote speaker to a crowd of 4,500 delegates, also extended the hand of friendship to Mr. De Klerk, urging him to join the democratic movement.
``Come stand on the floor of a conference like this,'' he urged De Klerk. ``Others from your community have stepped boldly forward, and found a home with the democratic movement.
``Submit to the process of democracy,'' Sisulu said. ``Act now so that we may minimize the damage to our people and our land.''
A declaration adopted by the conference expressed doubts about De Klerk's sincerity but added that, if he ``can convince us that he is serious about genuine negotiations ... we are ready to talk about the creation of a democratic South Africa.''
The conference failed to score any breakthrough toward black unity. The Zulu-based Inkatha Movement and the militant Pan Africanist Movement did not take part.
The only anti-apartheid group outside the fold of ANC-aligned groups that attended the conference was the Black Consciousness Movement (BCM).
Jerry Mosala, president of the BCM-aligned Azanian Peoples Organization struck a far more militant note than Sisulu. Conference debate, which took place behind closed doors, reflected unresolved differences between the two groups.
``The aim of the struggle is not negotiations but to destroy apartheid and capitalism,'' said Mr. Mosala in a speech in which he quoted from the American black leader Malcolm X. ``If we cannot restore access and control of the land to the people then we will have negotiated their freedom away.''
The conference achieved a broad mandate for the ANC's position on negotiations, demanding a sovereign Constituent Assembly as the vehicle for drawing up a new constitution. Pretoria wants to retain control of the constitution-making process.
Sisulu said a combination of anti-apartheid and international pressure, economic crisis, and the changes elsewhere in the world had put South Africa's ``back to the wall.''
``The regime has been forced into a state of transition,'' said Sisulu in his second major speech since he was freed two months ago. ``It cannot be certain that it can control the events which will result from these changes.''
But Sisulu warned that De Klerk's reforms were not the ``great beginning'' he claimed they were but rather an attempt to ``de-escalate the struggle'' and end South Africa's international isolation.
``Our grievance is our exclusion from political power and our objective is a transfer of power,'' said Sisulu. ``Segregated beaches have symbolized our exclusion, but their desegregation is not a transfer of power.''
Sisulu strongly criticized De Klerk's commitment to ``group rights'' - a euphemism for retaining political apartheid and ensuring that whites would retain a veto in a new constitutional dispensation.
But two days before Sisulu spoke, Constitutional Development Minister Gerrit Viljoen, a key De Klerk aide, told state-controlled television that the government did not regard ``group rights'' as nonnegotiable, but rather ``as part of the negotiating process.''
Last Thursday, Foreign Minister Roelof Botha wrote to United Nations Secretary-General Javier P'erez de Cu'ellar outlining a set of constitutional principles. The Pretoria document endorses the principle of racial equality with protection for minorities and equality for all before the law.