Egypt is rejecting Turkish arguments that a 2003 maritime deal with Cyprus to look for gas and energy off the divided island is “null and void,” saying the hunt will go on.

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In an interview with a Greek newspaper, Turkish Foreign Minister Mevlut Cavusoglu dismissed the 2003 agreement as no longer valid but Egyptian Foreign Ministry spokesman Ahmed Abu Zeid told Turkey to back off “any attempt to infringe on Egypt’s sovereign rights,” and dealings with Cyprus.

The northern third of the island has been occupied since an unlawful 1974 Turkish invasion and all attempts at reunification have failed for decades, the latest talks collapsing in July, 2015 at the Swiss resort of Crans-Montana when Cypriot President Nicos Anastasiades walked away after Turkey said it wanted to keep an army there and the right to militarily intervene when it wanted.

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.

Turkish President Recep Tayyip Erdogan has also warned global companies to stay away from any energy deal or face his wrath.

On Feb. 8 Cyprus announced that exploratory drilling by Italy’s ENI and France’s Total have discovered “extensive” gas reserves off the Mediterranean island, upping Turkey’s interest and setting the stage for a further escalation of tensions.

Energy Minister George Lakkotrypis said the data obtained “demonstrates the existence of an extensive column of pure gas,” the British newspaper The Daily Mail said in a report on the hunt for oil and gas off Cyprus.

Egypt, meanwhile, inaugurated in December the offshore Zohr gas field, said to be the biggest in the Mediterranean and discovered by the Italian firm ENI, one of those drilling off Cyprus.