Crans-Montana: - Talks to reunify the divided island of Cyprus collapsed amid anger and recriminations in the early hours of Friday, marking the end of a process seen as the most promising in generations to heal decades of conflict.

"I'm very sorry to tell you that despite the very strong commitment and engagement of all the delegations and different parties ... the conference on Cyprus was closed without an agreement being reached," United Nations Secretary-General Antonio Guterres said.

A girl holds up a board during a peace protest in the divided capital of Nicosia, Cyprus, on July 6. Credit:AP

The collapse marked a dramatic culmination to more than two years of a process that had been widely thought of as the best chance at reunification since the island was split between its Greek and Turkish Cypriot populations in 1974.

Mr Guterres had flown in on Thursday to press Greek Cypriot President Nicos Anastasiades and Turkish Cypriot leader Mustafa Akinci to seal a deal reuniting the east Mediterranean island, while US Vice-President Mike Pence had phoned to urge them to "seize this historic opportunity".