UNITED NATIONS, Jan 22 (Reuters) -- Security Council members expressed concern on Friday over a continuing military buildup along the Ethiopia-Eritrea border and the threat this posed for renewed hostilities.

The failure of recent mediation efforts and the concentration of troops along the 600 mile (960 kms) frontier has fuelled speculation of a resumption of fighting over contested border areas after a seven-month lull.

A statement read to reporters after the Security Council was briefed by the assistant secretary-general for peacekeeping, Ibrahima Fall, reaffirmed support for mediation efforts by the Organisation of African Unity (OAU) and urged both parties to cooperate fully.

``Council members reiterate their concern over the continuing military buildup along the common border between Ethiopia and Eritrea and about the implications of this buildup for renewed hostilities,'' council President Celso Amorim of Brazil said.

The statement welcomed Ethiopia's acceptance of a framework agreement proposed by the OAU, as well as the OAU's efforts to respond fully to requests by Eritrea for clarifications and Eritrea's engagement with the OAU process.

``Council members call upon both sides to exercise reason and restraint and to maintain their commitment to a peaceful resolution,'' the statement added.

It also commended peace efforts by United States envoy Anthony Lake and a decision by Secretary-General Kofi Annan to send U.N. trouble-shooter Mohamed Sahnoun to Eritrea and Ethiopia in support of the OAU efforts.