The United States is sending an aircraft to Eritrea to evacuate Americans as tension worsens in the Horn of Africa.

A BBC correspondent in the Eritrean capital, Asmara, says Britain is expected to take similar action.

The Eritreans have still to respond to a joint American-Rwandan initiative to resolve the border dispute with Ethiopia, which has led to serious clashes and the flight of thousands of refugees.

The Ethiopians say they support the initiative, but the Prime Minister, Meles Zenawi, said he could not tie the hands of the army if Eritrea remained in disputed territory.

The plan provides for an Eritrean withdrawal, the deployment of an observer force, the return of the previous civilian administration and an investigation of the rival claims.