Ukraine's gas debt to Russia will be almost $2 billion if the country fails to pay for February deliveries in full.
Speaking at a press conference, Russian President Vladimir Putin said that Ukraine's current debt stands between $1.5bn and $1.6bn.
Earlier, Russia's top gas producer Gazprom said it would remove a discount on gas prices for Ukraine starting from April.
More top news
Anything less than a Spurs win at Stamford Bridge tonight will mean Leicester City take the championship.
Parents will be taking their children out of school tomorrow in an unprecedented "strike" against compulsory exams for six-year-olds.
Sam Vokes sealed Burnley's return to the Premier League at the first attempt with a brilliant headed winner against QPR.