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By Maria Tsvetkova
MOSCOW, Dec 17 (Reuters) - Russian President Vladimir Putin said on Thursday he was not sure that the flow of Russian gas to Europe via Ukraine should end when a Gazprom transit contract runs out at the end of the decade.
Gazprom supplies about a third of Europe's gas needs and roughly half of this is shipped via Ukraine. But Gazprom plans not to renew the transit contact with Kiev after its expiry. In the past, rows between Moscow and Kiev have disrupted gas flows via Ukraine to Europe prompting a search for an alternative route.
"On a corporate level, during heated debates I personally heard someone saying we will stop the transit ... I am not sure this should be done," Putin said at his annual news conference.
Gazprom originally planned to use the South Stream pipeline beneath the Black Sea to send its gas to Europe. But this project has been scrapped and a different pipeline has been proposed - TurkStream - which would run to Turkey and then to Europe.
But there are also question marks over the TurkStream project.
Two Gazprom sources told Reuters last week that Russia could freeze work on TurkStream after Turkey shot down a Russian warplane last month.
TurkStream would initially carry a total of 63 billion cubic metres of gas per year.
Putin also said the European Commission should provide written guarantees that a possible future route for Russian gas flowing from Turkey to Europe would be a priority and supported by the Commission as a condition for Gazprom to continue the project.
Relations between Moscow and Ankara have been strained since the Russian plane was downed last month on a mission to Syria. Russia has imposed sanctions on Turkey.
In September, a group of European companies signed a deal with Gazprom to expand its Nord Stream pipeline so that it can deliver increased gas volumes directly from Russia to Germany but the expansion has not started yet.
Putin said on Thursday Russia's decision to participate in the construction of the Akkuyu nuclear power plant in Turkey would be based on purely commercial considerations.
"Questions about this project should be decided on a corporate level ... We will not take a single step that would damage our own economic interests," Putin told his annual news conference. (Reporting by Maria Tsvetkova, Alexander Winning and Christian Lowe; Writing by Maria Kiselyova/Katya Golubkova; Editing by Andrew Osborn and Jane Merriman)