Russian natural gas flows to Ukraine are stable, Ukrainian gas pipeline operator Ukrtransgaz said on Monday. Ukraine had received around 46.5 million cubic metres of gas on February 21, a spokesman said. Supplies from Russia's Gazprom resumed on December 9 after being cut off for six months due to a dispute over pricing and unpaid bills. Ukraine had 8.2 billion cubic metres (bcm) of gas in underground storage as of February 14, down by around 50 percent since the start of the heating season, Ukrtransgaz data showed.