The US State Department says it hasn't seen any evidence to show that Eritrean troops are withdrawing from Ethiopia.
This is despite the commitments that both countries had made that the troops would pull out, spokesman Ned Price said on Wednesday during a briefing with reporters.
"We urge their immediate full withdrawal, as we believe it is critical to restoring peace and security and critical to that issue of humanitarian access," he said.
The Eritrean soldiers have been in Ethiopia backing the government as it fought a group that challenged the central government's rule.
Troops from both countries have been accused of committing atrocities, with thousands dying from the conflict, according to human rights groups.