Turkey will only join talks to resolve decades of dispute over Cyprus with a proposal to establish two states on the island, presidential spokesman Ibrahim Kalin said on Thursday, adding previous failed proposals should not be on the agenda.

Turkish President Tayyip Erdogan said on Wednesday the only way to resolve the Cyprus dispute was a two-state solution, and a federation favoured by Athens and the island’s internationally-recognised Greek government would not be on the agenda of upcoming U.N.-led talks.

“We cannot discuss the things we discussed for 40 years for another 40 years,” Kalin told an interview with broadcaster TRT Haber, referring to decades of failed talks to unite the island.

On Monday the leaders of Greece and Cyprus said they would only accept a peace deal based on U.N. resolutions, rejecting the two-state formula supported by Turkey and Turkish Cypriots. Talks under United Nations auspices are planned for next month.

The U.N. is set to invite Cyprus’s two communities and foreign ministers from the three guarantor nations – Greece, Turkey and Britain – to discuss how to move forward on an issue that has stoked tensions between Ankara and Athens and complicated energy projects in the eastern Mediterranean.

U.N. resolutions call for Cyprus’ reunification under a two-zone federal umbrella. Previous attempts have failed to unite Greek and Turkish Cypriots on the island, which was split in a Turkish invasion in 1974 triggered by a Greek-inspired coup.

Turkish President Tayyip Erdogan said on Wednesday the only way to resolve the Cyprus dispute was a two-state solution, rather than a federation favoured by Athens and the U.N.

“Now, this issue will be discussed under the U.N.’s roof. It will be discussed at the 5+1 talks, we will now be discussing a two-state solution,” Kalin said.

On Thursday, a Turkish delegation led by Vice President Fuat Oktay held a second day of talks in the north of the island and agreed to further cooperation in a host of areas ahead of the planned talks next month.