The men had been prevented from leaving a Unita stronghold in the Central Highlands, which has been under attack from government troops, and UN officials had grown increasingly concerned for the peacekeepers' safety.

Unita leader Dr Jonas Savimbi

The towns of Bailundo and Andulo where they had been caught have come under a series of attacks by government forces. The towns are thought to be ringed by Unita's defensive positions and residents seem to have no way of leaving.

But the UN special envoy, Issa Diallo, told the BBC that following an agreement with Unita, the peacekeepers had been allowed to travel to the government safe-town of Huambo.

In 1994 the UN brokered a peace deal to bring an end to Angola's two-decade civil war between the government and Unita, that followed independence from Portuguese colonial rule in 1975. The National Unity Government was formed when the elected NPLA and Unita signed the peace accord.

Failing peace

On Friday the Secretary-General, Kofi Annan, said he would hold the Unita leader, Jonas Savimbi, personally responsible for the security of his peacekeepers. An emergency meeting of the UN Security Council was called, reflecting UN concern that the country is in danger of sliding back into full-scale civil war.

Diplomats have blamed Mr Savimbi for the recent disintegration of the peace process. They accuse him of refusing to hand over rebel-held territory to government control and opting instead to re-arm his forces.