ATHENS (Reuters) - The United Nations’ envoy for divided Cyprus said on Friday he was ending a shuttle diplomacy bid to continue peace talks in Geneva because rival sides had failed to agree on conditions.

FILE PHOTO: UN Special Adviser on Cyprus Espen Barth Eide (C) attends a demonstration by Greek Cypriots and Turkish Cypriots in favour of a peace settlement on divided Cyprus, at Ledra's checkpoint of the United Nations patrolled "green line" in Nicosia, Cyprus May 24, 2017. REUTERS/Yiannis Kourtoglou

Failure to agree on further negotiations effectively throws a two-year process of Cyprus peace talks into limbo, though the U.N. said talks had not collapsed. The island was split in a Turkish invasion in 1974 triggered by a brief Greek-inspired coup, and is a key source of tension between Greece and Turkey.

U.N. Cyprus adviser Espen Barth Eide is due to inform Secretary-General Antonio Guterres later on Friday and seek his advice on how to move forward.

He had been trying to get estranged Greek and Turkish Cypriots to move peace talks to Geneva, but the two sides disagreed on the format of negotiations.

“Unfortunately, despite serious efforts to overcome their differences regarding the modalities for meeting in Geneva, the leaders were unable to find common ground,” Eide said in a statement released by the U.N. mission in Cyprus.

“Without a prospect for common ground, there is no basis for continuing this shuttle diplomacy.”

The failure underscored pitfalls of a fragile reunification process fraught with difficulty in complex issues ranging from power-sharing and territorial adjustments - to the seemingly more mundane of agenda-setting at a peace conference.

Greek Cypriots wanted a conference in Geneva to first focus on clinching a deal on security arrangements post-settlement, while Turkish Cypriots sought a more inclusive give-and-take process.

It is a serious setback to a process which diplomats said was the best chance in decades to end Cyprus’s division, but diplomats said it was premature to draw conclusions.

“The talks have not collapsed. The process remains leader-led. We need to hear from them how they see the way forward,” a U.N. spokesman said, referring to Greek Cypriot leader Nicos Anastasiades and Turkish Cypriot leader Mustafa Akinci.