Angry demonstrators killed a Sudanese interpreter working with African Union forces in Darfur on Monday in riots that broke out during a senior UN official's visit to a camp for displaced Sudanese.
Jan Egeland, the UN under-secretary for humanitarian affairs, said the man was killed in an African Union police station after Egeland and his entourage beat a hasty retreat from the Kalma camp in the face of violent protests.
"After we left, the AU civilian police post was overrun and a member of the force was killed. He was a Sudanese interpreter," Egeland told reporters travelling with him.
Egeland and aid workers had cut short their visit to the camp in South Darfur State after a demonstration by Darfuris demanding the deployment of international troops spun out of control and an aid worker was attacked.
Tensions have increased among frustrated refugees who learned details of the peace pact signed on Friday in Nigeria between the Sudanese government and the main Darfur rebel group, but rejected by two other rebel factions.
They had hoped a deal would mean an end to three years of fighting that has driven 2 million people from their homes and into squalid camps in Darfur and into Chad.
But many said they were disappointed with the deal, which they feared did not go far enough to protect them.
"This peace is not reality," said Mohammed Jaama Sineen from Darfur's largest tribe, the Fur.
"We are asking for international forces. We want to ask Jan Egeland to send the UN to protect us," added the refugee who fled his home when rebels rose against the government in 2003 accusing officials in Khartoum of neglect.
Western governments have called for a UN mission to take over from the 7,000 African Union peacekeepers in Darfur. Sudan has said in the past it would only consider a UN mission in its vast west after a peace agreement.
Women wearing brightly coloured robes and men in white jalabiyyas gathered around shouting "Janjaweed, Janjaweed" then attacked a UN vehicle with axes, stones and sticks, shattering its windows.
One man tried to stab a Sudanese aid worker for the British charity Oxfam, who was beaten as he scrambled into the car while others tried to hold off the angry crowd.
Oxfam country director Caroline Nursey said the man was a trusted long-term worker for the organisation and the crowd had misunderstood something he said.