Moscow - Russia's Gazprom on Tuesday demanded a $1.66bn pre-payment from Ukraine for June gas deliveries, saying the neighbouring country had only half its requirements in storage to ensure a trouble-free winter.
Citing a preliminary bill, Moscow pressed ahead with its demand that Ukraine pay for June deliveries early next month, heightening a dispute over price that is pushing the two countries closer to another gas war that could cut supplies.
Previous disputes over gas have left Europe, which gets around a third of its gas needs from Russia, with limited supplies at the height of winter, spurring it to look for alternative producers. But so far it has been unable to break its dependence on Moscow.
Volumes
State-controlled Gazprom said the bill was based on Ukraine taking up a contractual amount of 114 million cubic metres per day, or 3.4 billion cubic metres for the month in total.
"Taking into account non-working days, Naftogaz should pay this bill by 2 June and, starting from 3 June, the company will be getting gas ... only at the volumes paid for," said spokesperson Sergei Kupriyanov in a statement.
This means that Ukraine needs to pay $1.658bn for June's gas deliveries based on a price of $485 per 1 000 cubic metres, he added.
Naftogaz confirmed it had received the bill but declined to comment further.
Punish
Ukraine wants to change the conditions of a 2009 contract that locked Kiev into buying a set volume, whether it needs it or not, at $485 per 1 000 cubic metres - the highest price paid by any client in Europe.
Moscow dropped the price to $268.5 after then-President Viktor Yanukovich turned his back on a trade and association agreement with the European Union last year but reinstated the original price after Yanukovich was ousted in February.
Kiev has so far refused to pay the higher price, saying gas is being used as a political tool by Moscow to punish Ukraine's new leaders for moving closer to the European Union.
Price cuts
Ukrainian Energy Minister Yuri Prodan called $268.5 per 1 000 cubic metres "a market and a fair" price for gas, which Kiev is able to pay.
He said Kiev would take Gazprom to court if the two sides failed to agree on price by 28 May, a procedure used by Gazprom's other clients in Europe to win price cuts over the last couple of years.
Twice in the past decade, price disputes have led to reduced supplies of Russian gas to European clients via Ukraine, a conduit for about half the gas Europe imports from Russia.