A large police operation is under way in the South African town of Ventersdorp where two men are expected to be charged in connection with the weekend killing of Eugene Terre'Blanche.
He was the white supremacist leader of the extreme right wing Afrikaner Resistance Movement.
Police used barbed wire to separate AWB supporters from local black residents.
Yesterday, the AWB retracted a threat to take revenge for the death of Mr Terre'Blanche.
Terre'Blanche was battered to death at his farm on Saturday following a suspected dispute over pay with two black farm workers.
AWB members initially described the killing as a declaration of war, but a spokesman said this had been a mistake.
'The AWB is not going to engage in any form of violent retaliation to avenge Mr Terre'Blanche's death,' said Pieter Steyn.
'We appeal for people to remain calm. Anyone engaging in any form of violence is not doing it as AWB.'
South African leaders, including President Jacob Zuma, have also urged calm since the killing.
But there is potential for violence at two events this week.
The AWB, whose flag resembles a Nazi swastika, has a tiny following among whites, who make up 10% of South Africa's population.
Afrikaner groups say anger in white agricultural communities has been growing because of a series of farm murders.
'Unfortunately if the government is not seen to do something very serious and effective now, people are going to take the law into their own hands,' Dan Roodt of the Pro-Afrikaans Action Group said.
