Jeremy Vine: Nkabinde was called both a thug and a hero

Bantu Holomisa was speaking at the funeral of UDM secretary general, Sifiso Nkabinde, who was shot dead on 23 January.

Mr Holomisa, who was military leader of the Transkei "homeland" in the apartheid era, said Mr Nkabinde's death must become the catalyst for peace.

"Let our voices be the guns and our votes the bullets," he said, referring to South Africa's second democratic elections later this year.

Holomisa: Let death be the catalyst for peace

Thousands of supporters attended the funeral in the town of Richmond, which turned into a political rally.

Over 1,000 police and soldiers had brought into the area for fear of futher violence, but the funeral went off peacefully.

Mr Nkabinde was a powerful figure in the region, who was expelled from the ruling African National Congress following accusations of spying and murder.

After being acquitted of murder, he joined the newly-founded UDM.

Our South Africa Correspondent Jeremy Vine says hatred between the ANC and UDM still runs deep in the region, and the killings might not yet be over.

Bitter dispute

Nkabinde: Joined UDM after expulsion from ANC

Richmond has been the scene of a bitter dispute between supporters of ANC and the UDM. Mr Nkabinde's murder sparked violent reprisals in which 11 people died.

The victims, including seven members of one family, were buried on Saturday amid a huge security operation.

The ANC's national chairman, Patrick "Terror" Lekota, who was in Richmond for the ANC funerals, blamed "enemies of democracy" for the violence.

Africa analyst Vincent Magombe: UDM feeding on insecurities

"There are elements who are determined to discredit this country, to discredit this democracy, to disillusion the people of this country, so that they cease to be excited about what they have achieved," Mr Lekota said.

The BBC South Africa Correspondent, Jeremy Vine, says that a week after the deaths, the police seem no closer to bringing the killers to justice.

No one has approached the police to testify about Mr Nkabinde's killing, even though he was shot in broad daylight in a crowded area - testimony to a situation where people are frightened to be seen to take sides.