CRANS-MONTANA, Switzerland (Reuters) - 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 told a news conference after a stormy last session.

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.

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 U.S. Vice President Mike Pence had phoned to urge them to “seize this historic opportunity”.

Diplomatic efforts to reunite Cyprus have failed since the island was riven in a 1974 Turkish army invasion triggered by a coup by Greek Cypriots seeking union with Greece.

The week of talks in the Swiss Alps, which the United Nations said was the “the best chance” for a deal, ground to a halt as the two sides failed to overcome final obstacles.

Diplomats said Turkey had appeared to be offering little to Greek Cypriots wanting a full withdrawal of Turkish troops from the island, although the Greek Cypriots had indicated readiness to make concessions on Turkish Cypriot demands for a rotating presidency, the other key issue.

Guterres finally called a halt at 2 a.m. after a session marred by yelling and drama, a source close to the negotiations said.

NOT ‘END OF ROAD’

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“Unfortunately... an agreement was not possible, and the conference was closed without the possibility to bring a solution to this dramatic and long-lasting problem,” Guterres said.

“That doesn’t mean that other initiatives cannot be developed in order to address the Cyprus problem,” he added.

Guterres declined to elaborate on what exactly had caused the collapse, but said there was still a wide gap between the two delegations on a number of questions.

Without a fallback option, it was unclear what, if any, peace process could continue. Reunification attempts have always been under the umbrella of the United Nations, which has one of its longest-serving peacekeeping forces on the island.

Turkish Foreign Minister Mevlut Cavusoglu, who with his Greek counterpart Nikos Kotzias had been attending the peace talks at the Swiss Alpine resort of Crans-Montana for a week, spoke of different options.

“This outcome shows the impossibility of reaching a settlement within the parameters of the Good Offices Mission,” Cavusoglu wrote on his twitter feed, using a term referring to the UN.

“No use in insisting on them.”

Greek Cypriots, due to launch gas drilling off the island in coming weeks that Turkey opposes, pointed the finger of blame at the Turkish side.

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Nicos Christodoulides, spokesman for the Greek Cypriot government, said Turkey had refused to relinquish its intervention rights on Cyprus or the presence of troops on the island.

“Tonight’s development is in no way positive, but it is not the end of the road either,” he said, without elaborating.

Guterres, who began his role in January by announcing a “surge of diplomacy for peace”, is known for his energy and drive.

But he appeared tired and downcast as he announced the collapse of the talks to a handful of journalists at an impromptu news conference that lasted only three and a half minutes.

Diplomats say that Cyprus should be much simpler to resolve than many other situations where the United Nations hopes for peace, such as the bloody and complex wars in Syria, Yemen, Ukraine, South Sudan, Libya, or the Korean peninsula.

Yet it is a conflict which has become deeply entrenched after years of stalemate and distrust.

Success in the Cyprus talks would have given Guterres a high profile at the G20 talks in Hamburg, where he is due on Friday, and where he will meet U.S. President Donald Trump, who has promised to cut the U.S. share of U.N. funding.