UPDATE 1-No Russian gas flowing to southeast Europe-Bulgargaz

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SOFIA, Jan 13 (Reuters) - Bulgaria's state gas monopoly Bulgargaz has been informed by Gazprom's (GAZP.MM) Balkan distribution unit that no Russian gas was flowing via Ukraine to southeast Europe, Bulgargaz said on Tuesday.

"We've been informed that there is no gas reaching Ukraine," Bulgargaz's chief executive Dimitar Gogov told Reuters.

Russia started pumping gas destined for Europe through Ukraine earlier on Tuesday for the first time in nearly a week, but the European Union said little or no gas was flowing to countries suffering urgent energy shortages.

Russia's state-controlled gas monopoly, Gazprom, accused Ukraine of siphoning off the gas for its own use. Ukraine blamed a lack of coordination for hampering the flow.

"I no longer know who to believe," Gogov said. "Russia says one thing, Ukraine says another."

A contract dispute between Moscow and Kiev has left European countries struggling for gas supplies with winter temperatures below freezing.

Bulgaria and the western Balkans are among the worst hit as they have no access to alternative pipeline routes and rely almost entirely on Russia for their gas. (Reporting by Anna Mudeva)