Ventersdorp, South Africa (CNN) -- Blacks and whites confronted each other Tuesday outside a courthouse where two people accused of killing a white supremacist leader in South Africa appeared and were charged with murder.
The two groups outside the courthouse in Ventersdorp sang rival national anthems, with whites singing "Die Stem van Suid-Afrika," an apartheid-era national anthem, while blacks sang "Nkosi Sikelel' iAfrika," which was sung as an act of defiance during the apartheid years.
The songs were combined to create the country's current national anthem, according to the government's Web site.
The two suspects, ages 15 and 28, were formally charged Tuesday with murder in the killing of Eugene Terreblanche. They also were charged with housebreaking, robbery, attempted robbery and crimen injuria, a count specific to South Africa in which someone deliberately injures another person's dignity.
Prosecutors said the count of crimen injuria related to the two suspects allegedly leaving Terreblanche's body with the pants pulled down.
The suspects, whom authorities have not identified, are accused of killing Terreblanche in a dispute over wages.
Terreblanche, 69, was bludgeoned with clubs and stabbed with a machete during the attack at his farm near Ventersdorp in South Africa's North West province, police said.
A new hearing has been set for April 14.
Outside the court, blacks and whites faced off in a brief scuffle apparently sparked by a white woman who threw a bottle at the black group.
Police erected barbed wire to separate the groups; the wire already surrounded the courthouse to prevent the crowds from swarming the building.
Riot police stood between the wire and about 200 of Terreblanche's followers -- some of whom were wearing army uniforms with swastika-like emblems on caps and shirts.
"We are here to show our solidarity with Terreblanche," said Pieter Steyn, a spokesman for the supremacist's neo-Nazi group Afrikaner Weerstandsbeweging, also called AWB. "The situation in this country is volatile," he said.
Some protesters carried signs, including one that read, "We are fed up with the new South Africa." Another sign said, "Soccer 2010, 65 days to chaos," an apparent reference to the start of the World Cup in the country.
A few blacks watched nervously. "These people are hurting. Their leader has been killed, and we don't know what they will do to us," one bystander said.
The AWB retracted its vow Monday to avenge the killing of its leader. "The statement was made by an emotional member of our organization," Steyn said. "The person has been reprimanded. We want a homeland where we can govern ourselves, and violence is not going to do our cause any good."
The AWB has blamed the killing on the singing of a controversial African National Congress song, "Shoot the Farmer."
Julius Malema, the ruling party's youth leader, had sung the apartheid-era song in recent weeks until a court barred him from doing so.
Steyn urged South African President Jacob Zuma to intervene. "We are finding it difficult to keep our members calm under the current circumstances. If farm murders continue, we cannot guarantee that our members will continue refraining from retaliating," Steyn said.
Zuma has appealed for peace. "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 in a Sunday statement.
The 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 a 1996 attempted murder of a black man who worked as a security guard on his 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