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
The Salisbury nerve agent attack has heightened tensions between Russia and the West. What is it like to be caught in the middle of the two?
The former national team boss was accused of intimidating a female official with a pole following the Lionesses' semi-final Euros defeat.
Cloudy at first in the south, with patchy rain slowly clearing and turning brighter.