With Western powers intensifying mediation to end a simmering border dispute, Washington warned its ally Ethiopia and the smaller Eritrea that they would jeopardize U.S. ties and aid if fighting erupted.

"The United States is concerned about the possibility of renewed hostilities between Ethiopia and Eritrea, which would have dire consequences for the people of the two countries," the U.S. State Department said in a statement.

U.S. Deputy Assistant Secretary of State for African Affairs Donald Yamamoto is due in the region this month, quickly following European diplomats who have aimed to cool the angry rhetoric between two of world's poorest nations.

Western governments are seeking to raise international awareness of the risks posed by heightened tensions between the neighbors after an estimated 70,000 people died in the 1998-2000 conflict in combat that often recalled the trench warfare of World War One.

The peace process has been stalled since Ethiopia refused to accept the ruling of an independent commission over where the disputed 600-mile (1,000-km) frontier should lie. A shooting on the border in November has underscored growing hostility.

Tensions between both countries have been rising ever since, prompting concern that continued deadlock could impede efforts to battle humanitarian crises affecting the countries that have been ravaged by food shortages.

"The United States urges both parties to implement the Eritrea Ethiopia Boundary Commission's decision peacefully, fully and without delay," the statement said.