Since the 1950s, there has been bad blood between Turkey and Greece over Cyprus. Turkey intervened in 1974 after a coup staged by supporters of union with Greece; the conflict has been frozen since then. Greek Cyprus joined the European Union in May 2004, only a week after the Greek Cypriot population by a decisive majority voted down the UN plan for the reunification of the island, adding to the complication of the conflict. EU-member Greek Cyprus has strengthened its international position at the cost of Turkish Cypriots.
The Greek Cypriot government therefore considered it to be its indisputable right to negotiate with foreign countries and international companies to explore and exploit the natural resources of the island without reaching an agreement with the Turkish Cypriots. In protest of that Greek-Cypriot approach, Turkish Cypriots signed an agreement with Turkey in 2011 calling for Ankara to prevent any unilateral move by the Greek Cypriot administration to explore hydrocarbon resources around the island, saying its natural resources should be exploited in a fair manner under a united Cyprus.