US firm Noble Energy has begun exploratory drilling for oil and gas off the coast of Cyprus, despite earlier warnings by Turkey that it will send warships to protect its claims to resources.Cyprus’ energy chief says US firm Noble Energy has begun offshore exploratory drilling for oil and gas. Solon Kassinis told the AP on Monday that rig workers have already drilled about 80 meters (260 feet) beneath the seabed inside the island’s exclusive economic zone, which is close to sizable gas finds within Israeli waters.Turkey escalated a dispute with Cyprus over oil and gas drilling in the eastern Mediterranean, saying Monday that it would send warships to protect its claims to resources off the coast of the divided island.Cyprus has said that it has political backing from the international community to drill for oil and gas off its shores.