Turkey’s president has called a maritime deal between Greece and Egypt “worthless,” saying Turkey will resume oil and gas exploration in the Eastern Mediterranean.

Egypt and Greece on Thursday signed a maritime deal that sets the sea boundary between the two countries and demarcates an exclusive economic zone for oil and gas drilling rights.

President Recep Tayyip Erdogan, speaking after Friday prayers in the recently reconverted Hagia Sophia mosque, said the deal was a response to Turkey’s maritime agreement with Libya’s Tripoli-based government last year and vowed to continue it.

That deal spiked tensions in the East Mediterranean region and was dismissed by Egypt, Cyprus and Greece as an infringement on their economic rights in the oil-rich sea.

Erdogan also said Turkey had paused research in disputed waters with Greece after a request from German Chancellor Angela Merkel. “I told (Merkel) we’ll pause drilling for three to four weeks if you trust Greece and the others … but I don’t trust them and you will see,” Erdogan said.

But that appears to have ended with the deal between Greece and Egypt.

“We have immediately resumed exploration activities,” Erdogan said and appointed Turkish research vessel Barbaros Hayreddin, which is sailing off the western coast of Cyprus.

Turkey has accused Greece of trying to exclude it from the benefits of oil and gas finds in the Aegean Sea and Eastern Mediterranean, arguing that sea boundaries for commercial exploitation should be divided between the Greek and Turkish mainlands and not include the Greek islands on an equal basis.

Athens counters that Turkey’s position is a violation of international law.