By Martin Plaut
BBC News Africa editor
Jacob Zuma put the comments down to youthful exuberance
Former Archbishop of Cape Town Desmond Tutu has called on an ANC youth leader to apologise for saying he was prepared to kill for party president Jacob Zuma.
The remarks by the head of the ANC youth league, Julius Malema, have caused considerable disquiet.
Mr Malema was speaking on one of South Africa's most emotive anniversaries - the commemoration of the 1976 Soweto uprising on 16 June.
The opposition Democratic Alliance urged the ANC to disown the remarks.
Mr Malema, his voice hoarse from public speaking, declared his unswerving support for Mr Zuma, who is facing corruption charges.
"Comrades, let's make it clear to everybody now. We are prepared to die for Zuma," he said.
"And not only that. If these people think we are only prepared to die, we are prepared to take up arms and kill for Zuma."
This week Mr Zuma - who was at the rally where the statement was made - played down the remarks as youthful exuberance.
"It was an unfortunate statement... I think the young man was trying to express a particular view… but he used the wrong words and I think it was an unfortunate statement," Mr Zuma said.
"They will grow up and [I] hope at one point they will be able to use the rights words for the right thing."
But others have taken it more seriously.
Archbishop Tutu called on Mr Malema to have the courage to apologise for the comment.
"When you say you're going to kill, even when you say it's not meant to be taken literally, it's unacceptable," said the Nobel prize winner.
The South African Human Rights Commission has also taken up the issue, giving Mr Malema until July to retract the statement.
But so far he has refused, saying: "Why do you apologise for something you did not mean?"