Russian natural gas giant Gazprom is set to slash gas supplies to Ukraine by an additional 25% at 8:00 p.m. Moscow time (17:00 GMT) today, which added to Monday's cut will bring deliveries down to half their normal level.
Dmitry Medvedev, who chairs the board of Gazprom and won a landslide victory in Sunday's presidential election, told President Viktor Yushchenko that Kiev must honor its commitments under an agreement reached with President Vladimir Putin in Moscow on February 12.
"Medvedev also said Russia expects Kiev to intensify efforts to settle the repayment of its natural gas debt as soon as possible," a spokesman for the first deputy premier said.
Gazprom reduced gas supplies to Ukraine by a quarter on Monday after failed talks on the country's outstanding debt of around $600 million, and on contracts for 2008 supplies. The company last cut supplies to the country at the start of 2006, causing temporary shortfalls in some European countries amid freezing temperatures.
During their phone conversation, Yushchenko and Medvedev pledged to do everything possible to ensure that Russian-Ukrainian relations develop positively.
The spokesman said: "Yushchenko congratulated Medvedev on his resounding [election] victory, and wished him success."
Medvedev will be inaugurated as president on May 7.