The massacre of 160 Congolese refugees in Burundi has brought the central African region to the brink of war, the UN peacekeeping chief has warned. Jean-Marie Guehenno asked all parties to show "maximum restraint", saying "there has to be justice, not revenge". Last week's attack on Tutsi refugees by a militia from the Hutu tribe has prompted threats of retaliation from the leaders of Rwanda and Burundi. The UN fears the charge that DR Congo backed the militia could lead to war. "This horrific massacre of Gatumba [refugee camp] must not lead to a cycle of revenge," Mr Guehenno said, after briefing the UN Security Council on the issue. Many of the victims were Tutsi women, children and babies, who had fled fighting in southern DR Congo in June. Armed with machetes, guns and grenades, attackers entered the camp on Friday evening and set fire to several shelters where they were living. A Hutu rebel group fighting Burundi's government later said it carried out the killings. But some sources say the rebels were aided by Hutu militias operating inside DR Congo, prompting Burundi's military chief to say he did not "rule out an offensive" in DR Congo. However, the Burundian president later said an attack "was not yet necessary". Rwanda and Burundi have already invaded DR Congo in the past, in search of the Hutu rebels blamed for killing thousands of Tutsis in the last decade. Mr Guehenno appealed to leaders to avoid the rhetoric of retaliation. "Now it's very important to make sure that all the leaders make the right statements, that there are no inflammatory statements," he said. Violence between the majority Hutu tribe and the minority Tutsis has afflicted the Great Lakes region of central Africa for over a decade. The genocide in Rwanda in 1994 and subsequent wars in Burundi and DR Congo have stemmed from it.