They claimed the IFP had been the victim of an African National Congress campaign of aggression which had sought to isolate and destabilise the organisation in an attempt to ensure its own political dominance.
But it could not be denied that individual party members had carried out violent acts, IFP president Mangosuthu Buthelezi told a special Truth Commission hearing in Cape Town.
"Although I have not orchestrated one single act of violence against one single victim of the political violence that has cost us many lives, as the leader of the IFP I know that the buck stops right in front of me."
He told a seven-member panel hearing his party's submission on its role in the apartheid conflict he had reservations about the commission's ability to uncover the truth about the country's past.
"I have decided to come here because we cannot in all conscience remain silent when no effort is made by this commission to question who has killed more than 420 of the IFP's leaders and murdered thousands of its supporters."
"These serial killings are a crime against humanity and demand answers."
The party's presentation took more than five hours as Buthelezi, IFP chairman Dr Frank Mdlalose and KwaZulu-Natal finance MEC Dr Ben Ngubane read out a 72-page document.
The submission gave the IFP's perspective of the "real" history of the liberation struggle, which claimed the ANC's violent response to apartheid and its ungovernability campaign had been the cause of today's violence and the conflict between the two organisations.
Buthelezi, who began his testimony by singing a hymn, said party leaders still had to work out their difference if there was to be peace.
"Today there is not mutual trust between me and Mr (Nelson) Mandela," he said, blaming the president for reneging on an agreement that there be international mediation "on the very causes of the violence".
While this issue remain unresolved there could never be "peace in this country, no matter what the (Truth) commission may do".
His criticism of Mandela followed an earlier apology to the President and other ANC leaders for "any hurt" he had caused them.
"I know that because we are human beings, and therefore sinners, that we shall still hurt each other even tomorrow. I nevertheless apologise for the past hurts and I do so also on behalf of my followers."
At a media briefing later, he played down the apology, saying he was merely repeating remarks made in 1991.
Stressing his opposition to violence, Buthelezi said: "It would be a hideous distortion of political reality to say that South Africans had to die on street corners from bombs planted there because if that did not happen, there would not be the prospects of political victories being won."
Mdlalose testified that the IFP had been the target of ANC destabilisation campaigns since a failed conference between party leaders in London in 1979.
"The differing strategies to overcome apartheid proved irreconcilable at that conference and from then on Inkatha was singled out as an enemy because it refused to crook the knee to the ANC or accept its strategy of armed struggle and the destruction of South African economy.
"The conflict between Inkatha and the ANC was not about apartheid. We were all against apartheid. The conflict was about the nature of the system that would replace white rule and the identity of those who would wield power after liberation," Mdlalose said.
Since the start of the armed struggle in 1961 some 14000 IFP supporters had been murdered in a campaign by the ANC/United Democratic Front to "liquidate" township administrations and render the country ungovernable.
Ngubane told the commission no rewriting of South African history should be allowed to "hide the fact that the ANC spent many years far more involved in fighting and killing their fellow black South Africans, than they spent involved in fighting the regime of the time".
Buthelezi said the party's appearance before the commission on Thursday did not mean the IFP would participate in future proceedings, although party members would not be discouraged from testifying.