Turkey has blocked a request from the Republic of Cyprus to take part in the global Conference on Disarmament in Geneva, as an adversarial relationship between the two countries is growing more intense.
Cyprus was among many countries that requested the right to participate as an observer in the first of three sessions this year of the 65-member Geneva-based body.
All but one of the requests were granted according to foreign media, with Turkey objecting to Cyprus for the first time.
The block came two days after Nicosia called Turkey a 'pirate state' over its attempts to drill for gas off Cypriot waters
A Turkish representative said Ankara had in the past refrained from blocking Cyprus' participation, by simply voicing its displeasure in a letter at the end of each session.
But this time was different.
"Turkey will not support this particular request this year," the Turkish official said.
The block came two days after Cyprus called Turkey a "pirate state" over its attempts to drill for oil and gas off Cypriot waters, and three days after the European Union had issued a warning to Ankara.
Nicosia has also been lobbying member states to move faster on sanctions against Turkey, in connection with Turkish drilling activities around the island.
While the European Union had condemned Turkish drilling around Cypriot waters, Nicosia had been frustrated with the lack of follow up after the EU had set up a mechanism to impose sanctions on any individuals or companies involved in what it described as illegal drilling in Cypriot EEZ.
In addition to maritime border disputes, Turkey has been actively pursuing a greater role in the eastern Mediterranean, including joining other foreign powers discussing the Libya situation as well as disrupting an alliance between Cyprus, Greece, Israel, and Egypt.
The Geneva Disarmament Conference is a multilateral disarmament forum that meets three times a year in Switzerland. The global forum negotiates arms control and disarmament accords and focuses on the cessation of the nuclear arms race.