The United States and Egypt warned Turkey against escalating tensions in the eastern Mediterranean over its attempt to drill for oil and gas in the waters off Cyprus, while the EU threatens with sanctions.

“The United States remains deeply concerned by Turkey’s repeated attempts to conduct drilling operations in the waters off Cyprus,” the State Department said, according to AFP. “We urge Turkish authorities to halt these operations and encourage all parties to act with restraint and refrain from actions that increase tensions in the region,” it said.

An Egyptian foreign ministry statement “stressed the importance of non-escalation and commitment to respecting and implementing international law”.

The discovery of huge gas reserves in the eastern Mediterranean has set off a race to tap underwater resources, sparking a dispute between Turkey and EU member Cyprus.

Cairo expressed its concern over Turkey’s “insistence to continue with unilateral measures that would increase tensions in the eastern Mediterranean region”.

Ankara’s Fatih vessel entered Cyprus’ exclusive economic zone in the west in May and has started drilling, while a second ship — the Yavuz — was deployed last month to search for oil and gas in the east.

The European Union said the latest move by Turkey was an “unacceptable escalation”, having warned Ankara to stop its “illegal” activities or face sanctions.