The presidents of Turkey and Russia on Wednesday formally launched the TurkStream pipeline which will carry Russian natural gas to southern Europe through Turkey, part of Moscow's efforts to reduce shipments via Ukraine. The pipeline project, stretching 930 km (580 miles) across the Black Sea, reinforces strong energy ties between Moscow and Ankara, which have also increased defence cooperation after Turkey bought advanced Russian missile defences last year. Russia and Turkey are also coordinating military deployments in northeast Syria, although they back opposing sides in the conflict in Syria's northwestern Idlib region and also in the battle for control of Libya. Presidents Vladimir Putin and Tayyip Erdogan inaugurated the project at a ceremony in Istanbul also attended by the leaders of Serbia and Bulgaria. The pipeline was a sign of "interaction and cooperation for the benefit of our people and the people of all Europe, the whole world", Putin said at the inauguration ceremony. Russia has already started European gas deliveries through the pipeline, gas operator Bulgartransgaz said on Sunday. The pipeline terminal is near the Turkish village of Kiyikoy, some 20 km (12 miles) from the Bulgarian border.

Russia is also doubling the capacity of Nord Stream across the Baltic Sea to Germany as part of plans to bypass Ukraine, which is currently the main route of transit to Europe.

Relations between Moscow and Kiev have deteriorated sharply since Russia annexed Crimea in March 2014 and pro-Kremlin separatists seized a swath of eastern Ukraine. Ukraine halted its own direct imports of Russian gas in November 2015.

Last month, the U.S. Senate approved a defence bill imposing sanctions related to both TurkStream and Nord Stream 2, as part of measures designed "to deter Russian aggression".

TWO PIPELINES Russian gas producer Gazprom will ship about 3 billion cubic metres (bcm) of gas per year to Bulgaria via TurkStream, replacing a route that formerly passed through Ukraine and Romania.

Gazprom shipped about 3 bcm to Greece and about 500,000 mcm to North Macedonia via that route last year.