Turkey is set to send a new ship on Thursday to search for oil and gas off Cyprus, in a move expected to escalate tensions after the EU called on Ankara to stop its "illegal drilling activities".
The region near the divided island is believed have rich natural gas deposits, triggering a race between Turkey and the internationally recognised Cyprus, which also plans to ramp up its exploratory activities in the eastern Mediterranean.
Turkish officials said the new vessel is the 229-metre (750-feet) Yavuz, which has previously drilled in the waters off several countries including Kenya, Tanzania and Malaysia.
The European Union on Tuesday lashed at Turkey over its plans to drill in the area, warning it was preparing "appropriate measures" in response.
The appeal came after Turkey's first drilling vessel, Fatih, started searching for gas and oil in the waters considered part of Cyprus' exclusive economic zone.
Cyprus has issued arrest warrants for Fatih's crew members and accused the ship of breaching the republic's sovereign territory.
That drew the wrath of Turkish President Recep Tayyip Erdogan.
"They will apparently arrest our boats' personnel. You will come off badly if you do so," he said at the weekend.
He added that Turkey would not back down from searching for gas "in those areas that are ours".
The island has been divided between the internationally recognised Republic of Cyprus and the northern third under Turkish military control since 1974, formed after Ankara's troops occupied the area in response to a coup sponsored by the Greek military junta.
Ankara says its actions abide by international law and that it is drilling inside its continental shelf. It granted exploration licences to Turkish Petroleum in 2009 and 2012.
Turkey opposes unilateral moves of exploration activities by EU member Cyprus off the Mediterranean and says Turkish Cypriots have rights to a share of the island's offshore resources.
Last month, Brussels and the United States urged Turkey to reconsider plans to start exploratory drilling off the island.
Energy giants Total of France and Italy's ENI are heavily involved in exploring for oil and gas off Cyprus as is ExxonMobil of the US.