A deadline for long-time foes Ethiopia and Eritrea to agree their shared border is to expire at midnight.
The date was set a year ago by the Ethiopia-Eritrea Border Commission which was created following a bloody border war between the two countries.
The commission says if it fails to hear anything it will consider the line it has drawn as the official border.
Both sides say they accept its ruling, but neither has moved their troops to their own side of the new boundary.
Some 80,000 people died during the 1998-2000 war.
The United Nations has a peacekeeping force of 1,700 charged with monitoring a security buffer zone.
The BBC’s Elizabeth Blunt in Ethiopia’s capital, Addis Ababa, says the commission can hardly be said to have succeeded.
Dec 2000: Peace agreement
Apr 2002: Border ruling
Mar 2003: Ethiopian complaint over Badme rejected
Sep 2003: Ethiopia asks for new ruling
Feb 2005: UN concern at military build-up
Oct 2005: Eritrea restricts peacekeepers’ activities
Nov 2005: UN sanctions threat if no compliance with 2000 deal
Its imminent disappearance leaves the two armies glaring at each other across a still unresolved border.
What was meant to be a demilitarised border is now thick with troops and bristling with weapons and representatives of the commission have not been able to get in to set up border markers, our correspondent says.
The two sides will not talk to each other and there is no obvious way to move the issue towards a more satisfactory conclusion, she says.
In the past few weeks there has been talk of UN involvement and perhaps the appointment of a facilitator to work with the two sides.
But so far no such initiative has been announced.
The Ethiopian and Eritrean leaders, Meles Zenawi and Isaias Afewerki respectively, were allies until after Eritrea gained its independence from Ethiopia in 1993.
Their rebel movements had fought together to overthrow long-time Ethiopian ruler Mengistu Haile Mariam.
The 1998-2000 war was ostensibly fought over the dusty town of Badme, which was subsequently awarded to Eritrea by the border commission.
But to this day the settlement remains under Ethiopian administration.
Meanwhile, Mr Meles has denied accusations made by separatist rebels in the south-east of Ethiopia that his troops have committed massive human rights abuses against civilians.
The rebel Ogaden National Liberation Front accused government forces of executing local residents during counter-insurgency operations in the region.
Mr Meles said such violations would not take place because his government respected human rights.
He said that given his own experience as a former rebel leader he knew that harassing civilians was the gravest mistake a government fighting an insurgency could make.