An informal meeting on Cyprus began in Geneva on Tuesday, with the UN chief seeking "common ground" for the resumption of talks to find a lasting solution to the decades-old dispute.
UN Secretary-General Antonio Guterres held separate meetings with the leaders of the Turkish and Greek Cypriots.
Ersin Tatar, president of the Turkish Republic of Northern Cyprus (TRNC), called his meeting with Guterres "productive," and said his side conveyed its views on the dispute to the UN chief.
"Guterres knows the Cyprus issue well. Now he will discuss the issue with the other side. We will discuss the issue intensively tomorrow and the day after," Tatar said.
Alessandra Vellucci, UN Information Service (UNIS) spokeswoman in Geneva, said that "the informal 5+1 Meeting on Cyprus in Geneva" had begun with a bilateral meeting between Guterres and Tatar.
Those talks were followed by a meeting between Guterres and Nicos Anastasiades, leader of the Greek Cypriot administration, at Geneva's Intercontinental Hotel, not far from the UN's European headquarters.
The UN chief hosted a reception for the heads of delegations later in the evening.
Foreign Minister Mevlüt Çavuşoğlu, Greek Foreign Minister Nikos Dendias, and UK Foreign Secretary Dominic Raab are leading the delegations of the guarantor countries.
UN chief is "realistic"
The plenary session of the talks is to start on Wednesday.
Ahead of the talks, Stephane Dujarric, spokesman for Guterres, had said: "The secretary-general is realistic. This is an issue that he knows well. He has participated in discussions before. So, he is realistic."
He said Guterres decided to call this "informal meeting" following consultations over the past several months.
"As we have repeatedly said, the purpose of this informal meeting will be to determine whether a common ground exists for the parties to negotiate a lasting solution to the Cyprus issue within a foreseeable horizon," said the UN spokesman.
Speaking on the 5+1 format, Dujarric said: "It is basically the leaders of the two communities, plus Greece, Turkey, and the UK. That format is really based on historical precedent."
Cyprus has been mired in a decades-long struggle between the Greek and Turkish Cypriots, despite a series of diplomatic efforts by the UN to achieve a comprehensive settlement.
The island has been divided since 1964 when ethnic attacks forced Turkish Cypriots to withdraw into enclaves for their safety. In 1974, a Greek Cypriot coup aiming at Greece's annexation led to Turkey's military intervention as a guarantor power. The TRNC was founded in 1983.
The Greek Cypriot administration, backed by Greece, became a member of the EU in 2004, although most Greek Cypriots rejected a UN settlement plan in a referendum that year, which had envisaged a reunited Cyprus joining the EU.