With the United States urging Turkey not to increase provocations in the Aegean, a Turkish energy research vessel was sent off the coast of Cyprus to explore for gas, with Turkish warships having earlier been stationed there to keep foreign companies from drilling for oil and gas.

The Turkish vessel Barbaros arrived in the area after the issuance of a NAVTEX advising all ships that Turkey intended to “conduct gas exploration inside Cyprus’ Exclusive Economic Zone EEZ),” parts of which Turkey doesn’t recognize.

Turkish Minister of Energy and Natural Resources Fatih Donmez said last week that Turkey had a drilling vessel off the coast of Cyprus to begin exploratory drilling for hydrocarbons on Oct. 29. Turkey has also increased its naval presence in the area, sending a frigate and three corvettes, the paper said, raising worries of an escalation of tension.

“Washington urged Turkey to refrain from actions that could further exacerbate tension in the eastern Mediterranean,” Ekathimerini reported.

ExxonMobil will search for natural gas off the cost of Cyprus by the end of the year, a top executive said earlier in October,, as Turkey renewed warnings against resource exploration in seas where it says it infringes on its rights and those of breakaway Turkish Cypriots.

Senior Vice President Neil Chapman said that exploratory drilling will begin “sometime in the fourth quarter.” He said ExxonMobil and partner Qatar Petroleum are focused on an area southwest of the Mediterranean island where they’re licensed to explore.

Chapman said the company hasn’t “looked in any detail” at an adjacent area, or block, for which the Cypriot government had invited bids for a drilling license.

The tender elicited another strongly-worded statement by Turkey’s Foreign Ministry, saying that Ankara “has never allowed and will never allow” any country or company to conduct “unauthorized research activities” inside waters it considers under its own jurisdiction.

Turkey claims parts of some blocks Cyprus has designated for drilling fall inside its own continental shelf. Turkey also argues that any hydrocarbon exploration ignores the rights of Turkish-Cypriots to the ethnically divided island nation’s natural resources.

(Material from the Associated Press was used in this report)