With Egypt joining Cyprus in the hunt for oil and gas off the island, Turkey – which unlawfully occupies the northern third – is further splintering relations and pushing Ankara to step up claims it owns the waters where the search is going on.

Unnamed political sources told the Chinese news agency Xinhua that the Egyptian-Cypriot ties and growing closeness has upset Turkey, which already has tense relations with Egypt and as it refuses to recognize Cyprus and is demanding a share of any revenues from potentially lucrative energy finds.

Turkey has also sent its own research vessel into the waters and had sent a warship there as well, and is ramping up belligerence in the wake of collapsed unity talks between Cypriot President Nicos Anastasiades and Turkish-Cypriot leader Mustafa Akinci.

Turkey recently declared its rejection of a 2013 maritime border demarcation agreement between Egypt and Cyprus that allows exploration for gas in the area, drawing fire from Egypt that it’s an infringement of that country’s economic rights in its Eastern Mediterranean’s exclusive economic zone (EEZ).

Turkish Foreign Minister Mevlut Cavusoglu said last week that his country considers the maritime border demarcation agreement “null and void,” adding that it “violates Turkey’s continental shelf” and Turkish warships are blocking an Italian company’s ship from going into Cypriot waters where the legitimate government has authorized drilling for an international consortium, including French and US companies.

Turkey claims part of Cyprus’s EEZ as its own continental shelf and Cavusoglu said no foreign country, company or vessel may conduct any unauthorized hydrocarbon or scientific research activity on Turkey’s continental shelf.

“Turkey and Cyprus have historical territorial disagreement and Ankara’s rejection of Egypt-Cyprus maritime demarcation deal indicates Turkish plans for gas exploration in the Mediterranean,” Tarek Fahmy, a political science professor at Cairo University told Xinhua.

Egyptian Foreign Minister Sameh Shoukry said the agreement with Cyprus was lawful and that Turkey, which has demanded a share of any potentially lucrative findings and has sent Egypt and Cyprus signed that agreement 15 years earlier to to set up an Exclusive Economic Zone in the eastern Mediterranean to increase exploration for gas in the area, and where the legitimate government has licensed international companies to drill, which Turkey opposes and warned them not to continue.

In an interview with a Greek newspaper, Cavusoglu dismissed the 2003 agreement as no longer valid but Egyptian Foreign Ministry spokesman Ahmed Abu Zeid told Turkey to back off “any attempt to infringe on Egypt’s sovereign rights,” and dealings with Cyprus.

On Feb. 8, Shoukry insisted on the “validity of the accord, ” in a statement to reporters, indicating Egypt would ignore Turkey and forge ahead.

Turkish Prime Minister Binali Yildirim cautioned the Cypriot government, a member of the European Union Turkey wants to join although it refuses to recognize Cyprus and bars its ships and planes, against “one-sided and dangerous” steps.