The leaders of Greece, Israel and Cyprus met in Athens on Thursday to sign a deal for an undersea pipeline that would carry gas from new offshore deposits in the southeastern Mediterranean to continental Europe - a move that has riled Turkey.
The 2,000-km (1,243-mile) EastMed pipeline is intended to provide an alternative gas source for energy-hungry Europe, which is currently largely dependent on supplies from Russia and the Caucasus region.
As now designed, the pipeline would run from Israel's Levantine Basin offshore gas reserves to Cyprus, Crete and the Greek mainland.
An overland pipeline to northwestern Greece and another planned undersea pipeline would carry the gas to Italy.
The project, with a rough budget of $6bn, is expected to satisfy about 10 percent of the European Union's natural gas needs. But it also is fraught with political and logistical complexities.
The race to claim offshore energy deposits in the southern Mediterranean has created new tensions between Greece and Cyprus, on the one side, and historic rival Turkey.
Ankara has raised the stakes with recent moves to explore waters controlled by the two EU member countries.
Cyprus and Greece are particularly disturbed that Turkey sent warship-escorted drill ships into waters where Cyprus has exclusive economic rights.
Cypriot President Nicos Anastasiades said the EastMed pipeline, while not aimed against Turkey, affirms that Greece and Cyprus hold sovereign rights to the waters they control.
Before departing for the Greek capital, Israeli Prime Minister Netanyahu said the three countries have established "an alliance of great importance" that would bolster regional stability and turn Israel "into an energy powerhouse".
Israeli Energy Minister Yuval Steinitz has said the EastMed pipeline would take up to seven years to build and that its advantages include being less vulnerable to sabotage and not crossing many national borders to reach markets.
Anastasiades said in a New Year's Day interview with Cyprus's Phileleftheros newspaper that the agreement sends messages in every direction.
"Especially under current conditions, it demonstrates the strong political will of the countries involved, as well as the European Union, that they don't accept Turkey's unlawful actions," Anastasiades said.
Turkish President Recep Tayyip Erdogan has said that no project can proceed without his country's consent following a maritime border agreement that Ankara signed with Libya's Tripoli-based government.
The Cypriot government has licensed Italian energy company Eni, France's Total, and the United States companies ExxonMobil and Noble Energy to carry out exploratory hydrocarbons drilling in the country's offshore economic zone.
On Thursday, the president of the self-declared Turkish Republic of Northern Cyprus condemned the EastMed project, decrying the exclusion of Turkey and Turkish Cypriots from it.
President Mustafa Akinci said in a statement that the project "contradicts geographical facts, [is] unreasonable in economic terms, and was decided on purely political concerns."
He said the pipeline's route was much longer and more expensive than other alternatives.
"Geographical facts indicate that exclusion of Turkey and Turkish Cypriots from the energy equation in the Eastern Mediterranean is impossible," Akinci said.