A new war could break out between Eritrea and Ethiopia if U.N. peacekeepers withdraw from a buffer zone along their disputed border, Secretary-General Ban Ki-moon warned Wednesday. Ban ordered the troops to temporarily withdraw from the Eritrean side of the border on Feb. 11 after Eritrea obstructed peacekeepers by restricting U.N. night patrols, supply routes and diesel fuel. He said Ethiopia told him that it would have a hard time accepting peacekeepers only on its side of the buffer zone. In a report to the U.N. Security Council, Ban urged Eritrea to restore the U.N.'s ability to patrol its side of the border. If that doesn't happen, the $113 million annual peacekeeping mission "could be terminated," leading to increased hostilities, he warned.

A 1,700-strong U.N. force has been monitoring a 15-mile wide, 620-mile long buffer zone between the two countries under a December 2000 peace agreement that ended a 2 1/2-year border war.

The Horn of Africa neighbors have been feuding over their border since Eritrea gained independence from the Addis Ababa government in 1993 after a 30-year guerrilla war.

Tensions between the two countries remain high because of Ethiopia's refusal to accept an international boundary commission's ruling in 2002 on the border demarcation, which awarded the key town of Badme to Eritrea.

The latest Eritrean obstructions to the U.N. peacekeeping mission follow a ban on U.N. helicopter flights in its airspace in October 2005. The Eritrean military now occupies of part of the buffer zone, Ban said.

Only 164 peacekeepers remain in Eritrea, mainly to guard U.N. equipment until it can be evacuated, Ban reported.

As a sign of rising tensions, he said, troops from both countries exchanged gunfire several times in recent months.

The U.N. chief warned if peacekeepers completely withdraw it "could result in an escalation of tensions in the border area with the risk of a resumption of open hostilities, despite declarations by the two parties that they have no intention to restart the war."

"There is still an opportunity for Eritrea to reconsider its position," Ban said.

But Eritrea's U.N. Ambassador Araya Desta dismissed warnings of a new war and said there was "no border dispute."

"We didn't ask the U.N. to withdraw. This was done without consulting Eritrea," he said.