"The members of the council were unanimous in that the way the peacekeepers of UNMEE (the U.N. force) have been treated in Eritrea is totally unacceptable," South African Ambassador Dumisani Kumalo, current council president, told reporters.

The United Nations has almost completely withdrawn some 1,700 troops and military observers from a buffer zone along the border between the two Horn of Africa rivals after Asmara cut fuel supplies to the mission.

Eritrea said countrywide shortages had prompted the move, but President Isaias Afwerki said last week the continued presence of U.N. peacekeepers on the Red Sea state's border with Ethiopia, scene of a 1998-200 war, was illegal.

The peacekeepers had been stationed in a 15.5-mile (25-km) zone inside Eritrea. But Eritrea turned against UNMEE because of U.N. inability to enforce rulings by an independent commission awarding Asmara chunks of Ethiopian-held territory.

Kumalo conceded that Eritrea had genuine concerns. He said the council would return to the issue, probably next week. "We have to take time to really think this through," he said.

U.N. Secretary-General Ban Ki-moon said in a report earlier this month that if the peacekeepers abandoned the 620-mile (1,000-km) border, a new war could break out, although both countries have said they do not plan to renew hostilities.

Ban offered several options, including the permanent withdrawal of UNMEE, deploying a small observer mission in the border area, establishing liaison offices in Addis Ababa and Asmara or returning to the original full deployment.

The last option, however, looks unlikely given Eritrea's refusal to discuss the issue.

"The United Nations cannot really achieve a result if the two countries do not follow up on the commitment they made in 2000," when they agreed to host UNMEE, U.N. peacekeeping chief Jean-Marie Guehenno, who briefed the council, told reporters.

Most UNMEE troops have been sent home temporarily and less than 200 are now in Eritrea, with a few in Ethiopia.

Ethiopia has offered to hold talks with Eritrea but Asmara says Addis Ababa must first withdraw from Eritrean territory. Both sides have amassed troops in recent months.

U.S. envoy Alejandro Wolff said there was "a mood in the council of great, great dissatisfaction at the manner in which Eritrea has handled this," and accused the Eritreans of "shooting themselves in the foot."

"In the long term Eritrea will pay a big price for this misjudgment," he told reporters, without elaborating.