The head of the United Nations force for Ethiopia and Eritrea has challenged both countries to state whether or not they want the force to remain
The UN has a tough job on the border
The ultimatum follows accusations from Eritrea that the UN force was harbouring criminals and endangering the security of the region.
The UN force (Unmee) patrols a 1,000km border between the two countries.
They fought a war between 1998 and 2000 that is thought to have killed more than 70,000 people.
Major General Robert Gordon said genuine concern was now being expressed about Unmee's viability, given the lack of progress on demarcating the border, and diminishing consent for the mission's operations.
According to an Unmee spokesman, the Eritrean delegation did then express support for the UN mission, albeit rather grudgingly, and said it hadn't intended to harm its work.
The Ethiopian delegation said the UN's mandate was clear and necessary and praised the UN staff for remaining calm and tolerant in what the delegation leader called a tense political environment.
The latest meeting between the two countries and the UN commander, took place in an atmosphere of heightened tension, after a week of bad-tempered exchanges between the peacekeepers and the Eritrean government.
Unmee complained that Eritrea was restricting its movement and harassing and detaining its local staff; the Eritrean government accused members of the UN force of paedophilia, harbouring criminals, using the Eritrean currency as toilet paper and endangering the security of the region.
The UN said it was shocked by the accusations.
The peace process has stalled since 2002, when Ethiopia rejected an international boundary commission ruling, demarcating their border.
This had awarded Badme, the symbolic town where the war started, to Eritrea.