UN Correspondent Rob Watson: "A predictable and somewhat formulaic statement"

The council issued its statement after a meeting in New York on the country's apparent slide back into full-scale civil war.

The statement said that members "expressed outrage for the disappearance of a second United Nations-chartered aircraft over the territories held by Unita".

Security Council president Celso Amorim of Brazil said Unita should cooperate "fully and immediately" with UN rescue requests that include demands for a ceasefire so search missions could be undertaken.

The UN said it also held the Angolan government responsible for the safety of its personnel.

A total 14 people were on board the first plane which crashed just after take-off from central Huambo on 26 December. Eight people were on the second, which came down on Saturday in similar circumstances after apparently being shot down.

Both flights were chartered by the UN peacekeeping mission in Angola, and the passengers were either UN peacekeepers or local employees with the mission.

The government and Unita have blamed each other for the shooting down of the planes.

BBC Correspondent Jim Fish: The UN could pull out of Angola altogether

UN Secretary-General Kofi Annan is to make his assessment to the security council on the issue next week and is likely to recommend a reduction if not a full withdrawal of the UN mission, at least until conditions improve.

Benon Sevan: Unacceptable situation

Council members are also awaiting a briefing from Benon Sevan, the top UN security coordinator, who arrived in Luanda on Monday in an effort to secure cooperation from both sides for the rescue operation.