Greece seeks emergency EU meeting on Turkey: PM
"The foreign minister (will) request an emergency meeting of the European Union foreign affairs council," Greek Prime Minister Kyriakos Mitsotakis' office said.
Marine tracking on Tuesday located the vessel southeast of the island of Crete. It is escorted by a Turkish navy flotilla and shadowed by Greek warships.
Turkey has announced the Oruc Reis would carry out activities between August 10 and 23.
Energy exploration in the gas-rich eastern Mediterranean is a frequent source of tension between Turkey and a bloc of its neighbours including Greece, Cyprus and Israel.
Greek Prime Minister Kyriakos Mitsotakis on Monday conferred with his military chiefs and spoke with EU Council President Charles Michel and NATO Secretary General Jens Stoltenberg.
EU foreign policy chief Josep Borrell on Sunday called Turkey's actions "extremely worrying" and a recipe for "greater antagonism and distrust".
Stoltenberg urged respect for international law during talks on Monday with the Greek premier.
"The situation must be resolved in a spirit of Allied solidarity and in accordance with international law," Stoltenberg tweeted.
Agencies contributed to this report.