UNITED Nations officials expressed fears of a new eruption of tribal violence after the apparent assassinations yesterday of the Presidents of the Central African nations of Rwanda and Burundi. Past bloodletting in the two states has resulted in the deaths of tens of thousands of people.

President Habyarimana of Rwanda and President Ntayamira of Burundi, both members of the Hutu tribe, were killed when the plane carrying them back from a one-day peace summit in Tanzania was shot down by rocket fire over the Rwandan capital of Kigali. Residents in the city said that they heard explosions followed by sporadic shooting.

UN officials in New York said that they were particularly concerned about the safety of the nearly 2,500 UN peacekeepers in Rwanda. The Security Council president appealed for calm.

Rwanda has been affected by fighting between Hutu and Tutsi tribes in neighbouring Burundi. Tens of thousands of people have been massacred after renegade troops killed Melchior Ndadaye, Burundi’s first Hutu President, in a coup last October. Hundreds more civilians died last month in a week of fighting in Bujumbura, the Burundian capital, between the army, dominated by the Tutsi minority, and mostly Hutu rebels. In Rwanda, wrangling between President Habyarimana’s government and the Tutsi-led rebel movement, the Rwandan Patriotic Front, has delayed implementation of a peace deal signed last year in the Tanzanian town of Arusha. The two Presidents had attended a one-day summit in Dar es Salaam to try to find a regional approach to prevent what President Mwinyi of Tanzania called “a Bosnia on our doorstep”.