Turkey will face a confrontation with Egypt if it does not respect Cairo’s rights for gas exploration won in a deal with Greek Cyprus, the Egyptian Foreign Ministry spokesperson Ahmed Abu Zeid warned on Tuesday.

The maritime border demarcation deal in question was signed in 2013 between Egypt and Cyprus, and gives Cairo access to an area of the East Mediterranean that is of particular interest for hydrocarbon companies since the discovery of the huge Zohr gas fields in 2015.

However, Turkey’s foreign minister Mevlüt Çavuşoğlu appeared to contest the deal, when he declared that Turkish Cypriots had been unfairly prevented from claiming their “inalienable rights to the natural resources” around the island, and revealed Turkish plans to begin exploration in the area.

“Nobody can contest the validity of the agreement,” the Turkish daily newspaper Sabah quoted Abu Zeid as saying in response, adding that the deal has been delivered to the United Nations.

Reuters reported that the foreign ministry spokesperson warned that “any attempt to infringe or diminish Egypt’s rights in that area” would be confronted.

Turkey’s relations with Egypt have been unfriendly since the current president, Abdel Fettah al-Sisi, deposed his predecessor, Mohamed Morsi, in a popularly-supported coup in 2013.