The European Union on Monday called on Turkey to show restraint and respect the sovereign rights of Cyprus in a dispute over exploiting energy wealth off the Mediterranean island.
During a visit to Cyprus, the EU's chief Brexit negotiator Michel Barnier reiterated the bloc's backing for the EU member after it gave Turkey a stern message at a summit in Romania this month.
"We express grave concern over Turkey's announced intention to carry out drilling activities within the exclusive economic zone of Cyprus," Barnier told reporters in Nicosia.
"We urgently call on Turkey to show restraint, respect the sovereign rights of Cyprus... refrain from any such illegal action," he added.
The senior EU official also suggested there would be consequences if Ankara persisted when saying the European Union "will respond appropriately and in full solidarity with Cyprus".
Cyprus President Nicos Anastasiades has slammed Turkey's drilling bid inside Cyprus waters as a "new invasion" and garnered support from fellow European Union leaders.
The United States, Israel and Egypt have also come out against Turkey's incursion into the island's EEZ.
"Turkey's actions, which are de-stabilising in the eastern Mediterranean region, have drawn broad condemnation from the international community," Cypriot Foreign Minister Nicos Christodoulides said after talks with Barnier.
He said Barnier was well aware of the need for the EU to "react collectively and decisively" to stop Turkey's violation of a member state's sovereign rights.
Turkey says its actions abide by international law and that it's drilling inside its continental shelf, but it does not recognise Cyprus as a sovereign or EU member state.
Cyprus has accelerated the development of offshore gas deposits and has signed deals with energy giants Eni, Total and ExxonMobil that have seen them carry out exploratory drilling.
US energy giant ExxonMobil discovered the largest natural gas reserve off the coast of Cyprus in February.
The "world-class discovery" is one of the largest finds worldwide in recent years with an estimated five to eight trillion cubic feet (141.5 to 226.5 cubic metres) of natural gas.
Ankara argues that such exploration deprives the Turkish Cypriot minority of benefiting from the island's natural wealth.
In February 2018, a drill ship for Italy's Eni abandoned an attempt to search for gas off Cyprus after it was blocked by Turkish warships.
Turkey has occupied the northern third of Cyprus since invading in 1974 in response to a Greek military junta-engineered coup aimed at uniting the island with Greece.
The breakaway northern part of the island declared independence in 1983, but it is only recognised by Ankara.