The presence of settlers in the island is one of the thorniest, most controversial issues in the ongoing negotiations to reunify Cyprus; the position of the internationally-recognised Republic of Cyprus and Greece, backed by United Nations resolutions, is that the settlement program is completely illegal under international law, as it violates the Fourth Geneva Convention (which prohibits an occupying power from willfully transferring its own population to the occupied area) and is a war crime.[18] The Republic of Cyprus and Greece thus demand that settlers be made to return to Turkey in a possible future solution to the Cyprus dispute; one of the main reasons that Greek Cypriots overwhelmingly rejected the 2004 Annan Plan was that the Annan plan allowed settlers to remain in Cyprus, and even allowed them to vote in the referendum for the proposed solution.[19] Both the Republic of Cyprus and Greece have therefore demanded that a future Cyprus settlement include the removal of settlers, or at least the greater part of them.[3][18]