KYIV, Dec 7 (Reuters) - The volume of Russian gas transported via Ukraine fell to 38.3 billion cubic meters (bcm) in January-November, or by 23.6%, compared to the same period in 2020, the state operator of the Ukrainian gas transmission system said on Tuesday.

Although gas transit increased to 3.049 bcm in November during cold weather from 2.634 bcm in October, its average daily level remained below the 109 mcm stipulated in Ukraine's five-year gas transit contract with Russia and the volume that Russia's Gazprom sent in the previous heating season.

Gazprom in recent years has cut its transit via neighbouring Ukraine, which has a history of gas pricing standoffs with Moscow.

Relations between Ukraine and Russia plummeted after Russia's annexation of Crimea in 2014 and the outbreak of war in eastern Ukraine. Moscow has also been developing other routes for transporting gas to Europe.

U.S. President Joe Biden and Russian President Vladimir Putin began virtual talks on Ukraine and other disputes on Tuesday, amid Western fears that Moscow is poised to launch a new offensive against its neighbour.

The head of Ukraine's state energy firm Naftogaz Yuriy Vitrenko said Russia could completely stop gas supplies through Ukrainian routes when their 5-year contract expires at the end of 2024 and redirect gas flows to the Nord Stream 2 pipeline.

Vitrenko said reliance on the Nord Stream 1 and 2 pipelines would make Europe more vulnerable to politically motivated supply disruptions and price spikes.

Russia says the pipelines are purely commercial. (Reporting by Natalia Zinets; Editing by Matthias Williams and Alexander Smith)