Sudan says its troops will stay in the disputed Abyei region despite an agreement with South Sudan to withdraw on Friday.
Khartoum says the troops will remain in Abyei until United Nations peacekeepers have fully deployed in the region.
A U.N. spokesman says only half of the 4,200 Ethiopian peacekeepers have arrived in Abyei.
South Sudan says Sudan never intended to honor the agreement to withdraw its forces. The south also says Sudan called off Friday's Abyei Joint Oversight Committee meeting.
Sudanese forces moved into Abyei in May, sparking an exodus of more than 100,000 people.
South Sudan became an independent country in July. A referendum on the future of Abyei never happened because Sudan and South Sudan could not agree on who qualified to vote.