MOSCOW, Oct. 11 - Leaders of Turkey and Russia signed a long-delayed deal Monday to build the TurkStream gas pipeline under the Black Sea to deliver Russian gas to Europe's doorstep within three years, Christian Science Monitor reported.

The pipeline is essentially supposed to bypass Ukraine, currently one of the major gas shippers, on the way to Europe, thus reducing the country’s revenue from gas transit.

The rapid warming trend in Russo-Turkish relations holds deep implications for Syria's immediate crisis, which dominated the talks and the subsequent headlines, but the fallout from that pipeline deal is a potentially crushing blow to struggling pro-Western Ukraine and may be rearranging strategic realities around the region for many years to come.

Acrimony is surging between Russia and the West over the situation in Syria. On Tuesday, Russian President Vladimir Putin angrily canceled a planned state visit to France later this month after French President François Hollande suggested Russia may be guilty of "war crimes," and wondered aloud whether meeting Mr. Putin at this time would be "useful."

But there was little sign of tension as Putin met Turkish President Recep Tayyip Erdogan on the sidelines of the World Energy Congress in Istanbul Monday. Though they back opposing sides in Syria, the two presidents amiably discussed ways to get humanitarian supplies into war-stricken Aleppo, then stood by smiling as the TurkStream deal was signed.

"I have full confidence that the normalization of Turkish-Russian ties will continue at a fast pace," Mr. Erdogan said.

Analysts say that if TurkStream goes ahead it will enable Moscow to cut its former main gas transit partner, Ukraine, completely out of the loop when current contracts expire in 2019. For Ukraine, it spells the loss of about $2 billion in annual transit fees paid by Russian gas monopoly Gazprom, which will make a huge hole in the struggling country's state revenues.

More importantly, it will also upend Ukraine's strategic dream of integrating with the European Union (EU) as the key energy hub that mediates Russian energy to the continent's thirsty markets.

Instead, the profits and geopolitical clout will pass to two countries that are otherwise friends of Ukraine. With TurkStream, Turkey will stand to become the chief distributor for Gazprom on the EU's southern flank.

And Germany, whose leading companies are backing the controversial NordStream II pipeline that will double Russian gas flow to the EU under the Baltic Sea, will become the undisputed main gas hub for northern Europe.

"The main idea of these pipelines is to circumvent Ukraine and punish it for its supposed unreliability," says Mikhail Krutikhin, a partner at RusEnergy, a Moscow-based consultancy. "Though neither of these pipelines is a completely done deal yet, the odds seem to be in their favor. It is a very big blow to Ukraine."

Gazprom's grand plan to abandon the Soviet-era infrastructure running to Europe from Ukraine first took shape in the form of NordStream I, which began channeling about 60 billion cubic meters (2.1 trillion cubic feet) of gas under the Baltic Sea to Germany in quieter times five years ago. That's 40 percent of Russia's total exports to the EU.

But the companion project, South Stream, which was meant to bypass Ukraine by carrying Russian gas under the Black Sea to Bulgaria, ran afoul of the geopolitical storms following Russia's annexation of Crimea, and was canceled in late 2014. (csm/ez)