The European Council said on Monday it was considering "appropriate measures" and would respond "in full solidarity with Cyprus" in light of the second exploration.
"The Council endorses the [European] Commission's proposal to reduce the pre-accession assistance to Turkey for 2020 and invites the European Investment Bank to review its lending activities in Turkey, notably with regard to sovereign-backed lending", it said.
In a statement on Monday the EU's foreign policy chief, Federica Mogherini, pledged the bloc would continue to stand by its most easterly member, describing the dispatch of the second drilling ship as an "unacceptable escalation".More news: Oil prices rise amid Gulf of Mexico storm, Middle East tensions
But past year, Brussels took away 175 million euros in protest at what it saw as deteriorating human rights in Turkey. Turkish officials say the drillships Fatih and Yavuz will drill for gas, which has prompted protests from Cyprus.
Last month the European Union threatened economic sanctions against Ankara.
"We reject the statements by the Greek Foreign Ministry and European Union officials which describe these activities of our country as illegitimate", the Turkish foreign ministry statement said. The move allows residents of the internationally recognised south and the breakaway Turkish Republic of Northern Cyprus to use their mobile phones on both sides of the Mediterranean island.More news: United Kingdom police launch investigation into leaked ambassador cables
The EU depends on Turkey to keep a lid on migration from the Middle East to Europe, and for security matters, but the relationship has turned sour over President Tayyip Erdogan's sweeping crackdown on critics following a failed coup in 2016.
Turkey's ruling AK Party spokesman said on Thursday that the sanctions against Ankara would be a huge mistake for the EU. "And it's obviously now for the council to take this forward", Kocijancic told reporters.
Turkish Cypriot reports said water bottles were thrown at the bus and damage was done to its side-mirrors by angry Greek Cypriots but who they were was not immediately confirmed.More news: Marvin Brooks leaves Love Island villa
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