UN Secretary-General Ban Ki-moon opened a two-day meeting with the partitioned island's rival leaders near New York City to discuss progress in talks started in 2008. Alexander Downer, the UN special envoy to Cyprus who oversees peace talks, said Ban spent nearly six hours with the two leaders.
"I think the best way to describe the talks today is that they have been intensive right from the very beginning," he told reporters.
"The secretary-general made his expectations clear this morning that he is looking for the leaders to make decisive moves," Downer said. "He also reminded the two leaders that they must keep the big vision of a United Cyprus in their sights."
Mediators want a deal ending decades of separation between ethnic Greeks and Turks on the Mediterranean island before Greek Cypriots, who represent the whole island internationally, take over the EU presidency in July.
"It's hard to see how it [the process] can go on then ... so we really have to get it done before July 1," Downer said earlier this month. "This process will come to an end when either there is an agreement or if there is complete deadlock."
Ban met with Cyprus President Demetris Christofias, representing the Greek Cypriots, and Derviş Eroğlu, who heads a Turkish Cypriot state recognised only by Ankara, at a private estate in the town of Manhasset on New York state's Long Island.
Cyprus, with a combined population of about 1 million, was torn apart in a Turkish invasion in 1974 triggered by a Greek-inspired coup. The conflict is a significant source of tension between NATO allies Greece and Turkey, and was thrown into sharper focus by a dispute over Mediterranean hydrocarbon riches recently discovered by Greek Cypriots and contested by Ankara.
Turkey has seen its aspirations to join the EU frustrated by the Cyprus stalemate and Greek Cypriots, who say Ankara cannot join the bloc until the division is resolved. Turkey says it will freeze ties with the EU when Cyprus assumes the presidency.
Both sides agree, on paper, in relinking Cyprus under a federal umbrella, but differ on how it is to work.
Downer said the United Nations would eventually like to have an international conference to resolve the issue, but cautioned that it was not clear if the two sides were ready for it.
"In an ideal world we would like to see convergences on all those [outstanding] issues and be able to move the whole process forward culminating in an international conference," he said.
"But to tell you the truth we will just have to see how we get on tomorrow before any judgments can be made by both the two sides," Downer said.
The United Nations is focusing on the electoral system in a future federated Cyprus, how to potentially settle property claims from thousands of people internally displaced, and future citizenship on an island whose demographics have shifted massively since division.
The United Nations says a convergence on these three issues would be considered a success, allowing the process to move ahead to talks on territorial adjustments and convening a multilateral meeting which would also involve Greece, Turkey and Britain, the island's guarantor powers.
In practice, diplomats say, the United Nations would be happy with a good outcome on just one of them - the electoral system.
Greek Cypriots have backed the idea of a rotating presidency under a weighted voting system. Turkish Cypriots advocate a separate ballot for each ethnic group.