US firm Noble has begun exploratory drilling for gas off the coast of Cyprus, ignoring Turkish warnings it would retaliate by launching its own explorations in the eastern Mediterranean.

Greek Cypriot energy chief Solon Kassinis told the semi-official Cyprus News Agency that Noble had started drilling for natural gas from its Aphrodite platform inside the island's exclusive economic zone on Sunday night.

On Monday, Turkey threatened to initiate a retaliatory gas and oil exploration if the Greek Cypriot government did not abandon the off-shore energy search.

Turkey's energy minister Taner Yildiz warned that Turkish naval ships would be ordered to escort energy exploration ships in the eastern Mediterranean unless Greek Cyprus immediately halted drilling plans.

"If Greek Cyprus sticks to the timetable it announced previously, we will start drilling activity next week," Yildiz told reporters.

"This work will be carried out together with the (navy) escort," he added. "There will be no turning back on this issue."

Yildiz called the drilling work a "provocation", warning that it could damage long-running reunification talks between Greek and Turkish Cypriots.

The Greek Cypriot government has warned that it will block Turkey's EU membership talks if Ankara continues to oppose its plans.

EU intervention

Turkey's EU bid has been hindered by the ongoing stalemate over northern Cyprus

The European Union weighed in on the dispute on Monday, calling on Turkey to avoid making threats.

"We urge Turkey to refrain from any kind of threat or sources of friction or action which could negatively affect the good neighborly relations and the peaceful settlement of border disputes," Maja Kocijancic, spokeswoman for EU foreign policy chief Catherine Ashton said.

Kocijancic also urged both countries to show restraint and work towards resolving the long-standing row. "The EU calls on all parties to make all efforts to reach a comprehensive settlement as soon as possible," she said.

For the past 37 years Cyprus has been divided between a Turkish north and a Greek south.

Turkey doesn't recognize Cyprus as a sovereign country and has repeatedly demanded that the internationally recognized Greek Cypriot government abandons energy exploration plans. The Turkish north has laid claim to any natural wealth found in the region.

Turkey has reportedly signed an agreement with a Norwegian company to commence seismic drilling off the island within a week.

Author: Charlotte Chelsom-Pill (AFP, Reuters, AP)

Editor: Rob Turner