New United Nations Secretary-General Antonio Guterres has cautioned against any "quick fix" in talks to forge a security deal for a reunited Cyprus.
The east Mediterranean island has been partitioned between ethnic Turks and Greeks since 1974 when Turkish forces invaded in response to an abortive Athens-inspired coup aimed at union with Greece.
Several hours after the start of the talks, there was little progress to speak of.
Flanked by Nicos Anastasiades and Mustafa Akinci, leaders of the island's Greek and Turkish Cypriots, Guterres said reunification talks had 'obviously a way to go'.
"You cannot expect miracles.. (an) immediate solution. We are not looking for a quick fix, we are looking for a solid and sustainable solution for the Republic of Cyprus and for the communities of the Republic of Cyprus," Guterres said.
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It is Guterres's first major involvement in a conflict which has been on the world body's agenda for more than half a century and hosts one of the world's longest serving peacekeeping forces.
British Foreign Secretary Boris Johnson said there was a "unique opportunity" to find a settlement.
"The fact that we have got this far is a real tribute to the courage and the determination of the leaders of the Greek Cypriot community and Turkish Cypriot community," he said in a post on social media.
"The most important thing clearly is that both communities should feel secure about their futures and that is what the British government is here to help with."
Greek Prime Minister Alexis Tsipras could join the summit if there are prospects for a solution, his spokesman said in Athens.
Property rights are also an emotive issue for thousands of people uprooted in the conflict.
Britain, the former colonial power in Cyprus, has offered to relinquish about half of the 98 square miles - equivalent to 3 per cent of total Cypriot territory - London still administers as part of any final peace deal.
