Russian natural gas volumes piped via Ukraine to European consumers rose 26 percent year-on-year in January to 7.6 billion cubic metres (bcm), the Ukrainian gas transport monopoly Ukrtransgaz said on Tuesday.
Ukrtransgaz gave no reason for the increase, as reported by Reuters.
More than a third of Russia's gas exports to the European Union currently cross Ukraine, providing Kyiv with valuable income. Russian gas giant Gazprom has said it wants to bypass Ukraine by building new pipelines.
Russian gas exports via Ukraine fell by 7 percent in 2018 to 86.8 bcm.
Relations between the two countries have deteriorated since Russia annexed the Crimean peninsula in March 2014 and Ukraine halted its own imports of Russian gas in 2015.