(CNN) -- South African President Jacob Zuma appealed for calm Sunday amid fears the killing of notorious white supremacist Eugene Terreblanche could stoke racial tensions in the country.
Terreblanche, the leader of the neo-Nazi Afrikaner Weerstandsbeweging (Afrikaner Resistance Movement, or AWB), was killed Saturday following an apparent dispute over wages with workers on his farm, according to South African police.
Police said the 69-year-old was bludgeoned and stabbed to death with clubs and a machete in an attack at his farm near the town of Ventersdorp in South Africa's North West Province.
Two of his farm workers ages 21 and 16 turned themselves in to authorities in connection with the killing and will appear in court on Tuesday, they said.
In a statement on the South African presidency's Web site, Zuma said he had spoken to Terreblanche's daughter to express his "sincere condolences."
"I call upon our people, black and white to remain calm, and allow police and other organs of state to do their work," Zuma said.
"This is not the time for speculation that can worsen the situation. It is the time for us to unite all of us, black and white and put the nation and the country first."
The AWB also urged its members and supporters to be calm as they mourned their leader.
Terreblanche's death comes amid a time of racial polarization in the country.
A South African court last month banned the playing of a political song called "Kill the Boer," most recently sung by radical youth leader Julius Malema. The apartheid-era song's lyrics translate to "kill the farmer."
South African civil rights group AfriForum condemned the killing and also called for calm in a statement on its Web site.
"These events are a call to all South Africans to come to their senses and to be aware of the extremely polarized and violent circumstances presently prevalent in the country," the statement said.
The group also said that "all communities -- white, as well as black -- should refrain from reckless statements and from romanticizing violence."
Terreblanche's AWB is best known for trying to block South Africa's effort to end apartheid. The group used terrorist tactics in a bid to stall the country's first all-race vote in 1994, killing more than 20 people in a wave of bombings on the eve of the elections.
Terreblanche was convicted of the 1996 attempted murder of Paul Motshabi, a black man who worked as a security guard on Terreblanche's farm. He served about two-thirds of a five-year sentence.
He was also convicted of setting his dog on a black man in an earlier incident.
CNN's Robyn Curnow contributed to this report.