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
Rain will affect most of the UK today, with Scotland remaining largely fine and brighter spells appearing in the east and south.
In a searingly emotive address, the president cast Hillary Clinton as the most qualified candidate to unify America as next US president.
The release is the second batch in a series of leaks that have rattled the Democratic Party.