Council members voted unanimously to withdraw the remaining peacekeepers from what was once a 1,700-strong force monitoring a 620-mile-long buffer zone between the Horn of Africa neighbors.

Belgian Ambassador Jan Grauls told the council that the mission, known as UNMEE, "had become impossible to implement" because Eritrea progressively limited the peacekeeper movements, supply routes and the supply of diesel fuel.

The mission was also undermined by Ethiopia's refusal to accept an independent boundary commission's ruling in 2002 to award the town of Badme to Eritrea, Grauls said.

"The border dispute between Ethiopia and Eritrea remains total, and the United Nations is withdrawing without having been able to assist the two countries in finding a common ground, in spite of having tried all to achieve it," he said.

Mission officials said about 320 peacekeepers remain on the Ethiopian side of the border but most of their colleagues on Eritrean side have already left. They said the "formal liquidation" of the headquarters in Addis Ababa, Ethiopia, and Asmara, Eritrea, would begin Friday.

The mission, which cost about $113 million a year, also has fewer than 400 civilian staffers still in place, mainly responsible for guarding U.N. equipment until it can be evacuated.

Secretary-General Ban Ki-moon, who warned in April of the dangers of ending the mission, wrote the council Monday cautioning that the risk of "a resumption of hostilities, by accident or design, following the withdrawal of UNMEE remains a reality."

Troops from both countries have exchanged gunfire several times in recent months, he said.

Ban included letters from Ethiopian Foreign Minister Seyoum Mesfin saying the Security Council could have done more to protect the mission and Eritrean Ambassador Araya Desta saying the council should have thrown its weight behind the boundary commission's ruling.

In a statement after the council vote Wednesday, Ban urged the two nations to "break the current stalemate and create conditions necessary for the normalization of their relations, which is key to peace and stability in the region."

Wednesday's resolution demands that Ethiopia and Eritrea comply with their previous agreement "to show maximum restrain and refrain from any threat or use of force against each other, and to avoid provocative military activities."

Eritrea and Ethiopia have been feuding over their border since Eritrea gained independence in 1993 after a 30-year guerrilla war. The U.N. sent in peacekeepers under a 2000 peace agreement that ended a 2 1/2-year border war in which at least 70,000 people died.