WINDHOEK, NAMIBIA — BLACK leaders in South Africa have closed ranks in a bid to save a national peace convention following the worst outbreak of political violence this year.Rival black leaders said Sept. 10 that the renewed wave of violence, which has already claimed 60 lives, should not be allowed to derail the signing of a peace accord on the weekend of Sept. 14. The accord, which follows three months of negotiations, seeks to lock the African National Congress, the Zulu-based Inkatha Freedom Party, and the ruling National Party into a peace pact. "We are going to the convention to ensure that we sign that document," said ANC President Nelson Mandela. "If every party adheres to the obligations that are set out in that convention we should be able to contain the violence," he said. Mr. Mandela said he was confident the three-way accord had more chance of succeeding than a peace agreement he and Inkatha leader Chief Mangosuthu Buthelezi signed in January. Inkatha national chairman Frank Mdlalose said Sept. 9 it was significant that violence had escalated only days before the signing of the peace accord. "What has happened is all the more reason for the peace process to work and to be made to work," he said. The violence erupted Sept. 8 in the township of Tokoza near Johannesburg when Inkatha supporters were gunned down on their way to a political meeting. "The peace accord to be signed on Saturday [Sept. 14] contains mechanisms which will help us get to the bottom of attacks such as these and bring the perpetrators to justice," said Anglican Archbishop Desmond Tutu. Archbishop Tutu described the attack on the Inkatha supporters as "vicious and cowardly. It is possible than those who planned the attack attempted to derail the peace summit," he said. The right-wing Conservative Party has refused to sign the peace accord because, it says, it is not involved in the violence. But there are signs of a willingness to negotiate by some right-wing factions following Mandela's visit to three right-wing hunger-strikers last week. The hunger-strikers, who had been fasting for between 48 and 62 days, ended their strike Sept. 9 without winning their demand for immunity from prosecution on murder charges. A police spokesman said Sept. 9 three unidentified black gunmen were being sought in connection with the attack. They fired on the crowd with automatic rifles from a house. Most of the 23 people killed in the attack were Inkatha supporters. At least 22 people were wounded. The attack sparked off a wave of retaliation by Inkatha supporters in Soweto and other black townships near Johannesburg, including Katlehong and Tembisa. Mobs of Zulu hostel-dwellers, armed with spears, hatchets, and machetes went on a rampage Sept. 8 killing township residents in their homes. Three black commuters were shot dead and thrown from a moving train on Sept. 9, and four others were seriously wounded. Previous violence between the rival black groups' supporters has disrupted efforts to reach a political settlement in South Africa and claimed thousands of lives. The violence has been fanned by clandestine government support for Inkatha and elements in the security forces sympathetic to the Zulu-based organization. The accord establishes independent mechanisms to monitor the security forces and make them accountable to the community at large. It also establishes a code of conduct for the police and for political parties. The agreement will also lead to the setting up of a national commission to investigate claims of security-force collaboration in the violence.