Turkey and Greece announced rival military exercises in the eastern Mediterranean for Tuesday as Germany prepared to take another crack at defusing the NATO allies' escalating row over natural gas.

The discovery of major deposits in waters surrounding Cyprus and the Greek island of Crete has triggered a scramble for energy riches and revived old regional rivalries.

Tensions ratcheted up another notch when Turkey sent the Oruc Reis research vessel accompanied by warships to disputed waters on August 10.

Greece and its EU ally France both dispatched their own naval assets to the area to monitor Turkey's work.

EU foreign ministers convened an emergency video conference on the emerging crisis when a Turkish frigate collided with a Greek one in disputed circumstances days into the Oruc Reis mission.

AFP