SOWETO, South Africa (AP) _ The king of the Zulus urged thousands of armed supporters Sunday to curb the factional fighting that has caused almost 800 deaths in black townships around Johannesburg.

''Everybody must lay down their arms and take their brother's hand in friendship,'' Zulu King Goodwill Zwelithini told fellow tribesmen in Soweto and Tokoza, two townships that have been hard hit by the fighting, which began in early August.

Zwelithini shared the stage at the peace rallies with President Tutor Ndamase of the Transkei, the tribal homeland of the Xhosas. The Xhosas have joined fellow African National Congress supporters in clashes against Zulus loyal to the conservative Inkatha movement.

Both sides blame the other for the fighting.

But on Friday, ANC leader Nelson Mandela said South African President F.W. de Klerk now believes some of the violence may be instigated by a ''hidden hand,'' an apparent reference to right-wing whites and others opposed to de Klerk's efforts to attain power-sharing between blacks and whites.

''I have come to this place to put out the flames of violence,'' said Zwelithini at the two rallies attended by more than 30,000 Zulus, many wearing wearing red headbands and brandishing axes and spears.

His speech was followed by a similar plea from Ndamase.

''Freedom is your goal, not bloodshed. Unity is your goal, not division. Power is your goal, not this bloody weakness,'' said Ndamase, who is Zwelithini's uncle.

Following the rally in Soweto, a Zulu was injured after being set on fire by rival blacks, witnesses said. No other incidents were reported.

Both leaders are considered ceremonial figures rather than political leaders, and it was unclear whether their calls for peace would slow the unrest. Neither holds an offical post in either the ANC or Inkatha.

''There is nobody who is entirely blameless,'' the king said of the fighting. ''We decided to come together to stand before the whole world to tell our people to stop this senseless black-on-black confrontation.''

Police initially threatened to disarm the Zulus. But the Zulus refused to give up the weapons, which they consider part of their traditional uniform necessary for tribal events. After negotiations, police gave in.

At the rallies, chiefs dressed in animal skins mingled with youths wearing T-shirts with messages such as: ''Inkatha,'' ''Victory Through Peace'' and ''Don't Worry, Be Happy.''

The rallies came a day after police announced operation ''Iron Fist,'' a crackdown in the townships that will include roadblocks, sending in reinforcements and possibly imposing curfews.

Police also said they would mount machine guns on armored patrol vehicles to curb the growing number of attacks on police in the townships.

Mandela predicted the measures would be ineffective and claimed they were announced only because two white policemen were killed in the past week.

The government last month sent police and army troops into the townships and imposed emergency regulations.

Police reported the townships around Johannesburg were quiet on Sunday.

The ANC and Inkatha, the two largest black political movements, both oppose apartheid but differ over tactics and plans for a future South Africa. The left-leaning ANC favors some degree of government economic control while Inkatha champions free-market measures.

Under the apartheid system of racial segregation, the 5 million whites dominate politics and the economy. The nation has nearly 30 million blacks.