MOSCOW, May 13 (Xinhua) -- Russian gas monopoly Gazprom has informed its Ukrainian counterpart that supplies of natural gas will be conducted under prepay option starting June, the company said Tuesday.
"(Ukraine's) outstanding debt has reached 3.505 billion U.S. dollars," Gazprom spokesman Sergei Kupriyanov told reporters.
"No one can doubt that this is a considerable and objective reason to invoke the provision figuring in the contract on the prepayment," the RIA Novosti news agency quoted him as saying.
Ukraine's Naftogaz should be buying 114 million cubic meters per day for 485 dollars per 1,000 cubic meters in line with the "take-or-pay" scheme, according to Gazprom.
For that, Naftogaz must prepay Gazprom for June's supply of 3.42 billion cubic meters worth 1.659 billion dollars, Kupriyanov said, adding that the money must be transferred to Gazprom's account before June 2.
In 2010, Russia and Ukraine signed a gas-for-fleet agreement, with Moscow offering a discount for gas in exchange for extending its lease of the Black Sea Fleet in Crimea for another 25 years.
In April, Kremlin declared the pact no longer valid as Crimea joined Russia in March. Following the announcement, Gazprom canceled discounts on gas supplies to Ukraine and set a price tag of 485 dollars, which Kiev has called overpriced and temporarily suspended gas intake.
Kiev has said it needed up to 30 billion cubic meters of natural gas to cover Ukraine's demand in 2014, with part of that volume to be covered by reverse gas supply from Europe.
On Monday, Russian Prime Minister Dmitry Medvedev asked Gazprom's CEO Alexei Miller to switch gas supplies to Ukraine to the pre-payment mode.
"It's time to stop nursing them. Inform them and introduce prepayment effective tomorrow," Medvedev said during a meeting with Miller, which also was attended by Energy Minister Alexander Novak.