A second day of negotiations between Cypriot President Tassos Papadopoulos and Turkish Cypriot leader Rauf Denktash, hosted by UN Secretary General Kofi Annan, broke up after less than 90 minutes on Wednesday.
Both Papadopoulos and Denktash declined to comment as they left UN headquarters in New York.
UN officials were also mum, signalling differences may have persisted for a second day running.
Annan is seeking an agreement on a work programme and ground rules for later technical talks in Cyprus to resolve disagreements and fill in the details of a reunification deal.
He wants Papadopoulos and Denktash to accept a previously drafted UN blueprint as the basis for their work, and he wants the negotiations wrapped up by March.
At that point, he wants to be able to fill in any blanks in a peace deal that would then be put to separate referendums in the Turkish Cypriot north and Greek Cypriot south on 21 April.
But both sides are strongly resisting Annan's demand that he be allowed to set terms on points on which the parties can not agree, diplomats close to the talks said.
Both sides are pushing hard for an alternative mechanism to break deadlocks, the diplomats said, adding that the talks are continuing in large part because neither side wants to be seen as responsible for blocking a deal.
Tayyip Erdogan (R) has been accused
of betraying Turkish Cypriots
Papadopoulos later told reporters that both Greek and Turkish Cypriots had submitted proposals during Wednesday's talks.
The Greek Cypriot side proposed, among other things, that the EU be involved in the technical talks, Papadopoulos said, adding that he hoped this would be accepted by both Annan and the Turkish Cypriot side.
Cyprus has been divided since 1974 when Turkish troops occupied the north of the island in response to a coup in Nicosia engineered by the junta then ruling Greece.
Turkey alone recognises Denktash's statelet in the north and still bases some 30,000 troops there, while the Greek Cypriot government in the south, with fewer than 5000 Greek troops on its soil, is widely recognised and will enter the European Union with or without a reunification deal.
Pressure on Denktash
Turkey, fearful that failure to reach an agreement will damage its own hopes of entering the EU, has put heavy pressure on Denktash - who was widely blamed for the collapse of an earlier round of talks last March - to reach a deal.
The European Union and the United States are also pushing hard for an agreement.
But Denktash, who has made no secret of his distaste for Annan's blueprint, has strong support from Turkish nationalists.
Opposition parties, appealing to Turkish nationalist sentiment ahead of local elections next month, have accused Turkish Prime Minister Tayyip Erdogan of preparing to "betray" the Turkish Cypriots to save Ankara's EU candidacy.
The principal disagreements centre on the division of power between a central government and Greek Cypriot and Turkish Cypriot zones in a federal state; fixing a new border between the two zones; and carrying out any population relocation dictated by the new border.
Another key issue is security arrangements including the continued stationing of foreign troops on Cypriot soil after it joins the EU.