RIA Novosti

The EU has been warned of another potential winter gas war between Russia and Ukraine which could affect fuel supplies to much of Europe.

A spokesman for Vladimir Putin said that the Russian Prime Minister spoke to his Swedish counterpart Fredrik Reinfeldt by telephone, after uncovering concerns that Ukrainian president Viktor Yushchenko was blocking payments for Russian gas supplies.

"During the meeting, Vladimir Putin focused the attention of the EU leadership on signals coming in, including through official channels from Kiev, regarding potential problems with payment for gas supplies," the official said.

Putin warned that payment problems could lead to difficulties for European consumers receiving Russian gas via Ukraine. A dispute between Moscow and Kiev at the start of the year over gas debts and 2009 deliveries left millions of Europeans without gas in January.

The Russian prime minister said on Friday that his Ukrainian counterpart, Yulia Tymoshenko, had told him by telephone that President Viktor Yushchenko was blocking payments for Russian gas supplies.

The Russian prime minister said that IMF data showed Ukraine had gold reserves of $27-$28 billion, with a maximum of $12 billion required to cover the payment. He also noted that the European Union had refused to extend any loans to Ukraine to cover its gas purchases.

Kiev asked the EU for a $4.2 billion loan to pump Russian gas into its underground storages in order to avoid problems with gas transit to Europe.

"The EU has not given Ukraine any money," Putin told leaders of his United Russia party on Friday. "Ukraine has not received a single cent, not one hryvnia."

Kiev on Friday rejected Putin's "unfriendly" comments, in a statement from the president's representative for international energy security issues Bohdan Sokolovsky."

"On July 30, the European Commission and three honorable international financial institutions published a joint statement on a $1.7 billion loan to buy Russian gas. However, the head of the Ukrainian government is still slow at fulfilling the conditions in order for these funds to be transferred," Sokolovskiy said.

Last January's standoff was resolved after negotiations between Putin and Tymoshenko that led to Russian energy giant Gazprom and Ukrainian state energy company Naftogaz signing new contracts on deliveries to Ukraine and gas transit to Europe.

That deal has been consistently opposed by Yushchenko, who has repeatedly called for the contracts to be revised, saying that Naftogaz had lost at least $2.5 billion from Russian natural gas transit.

Russia supplies around one fifth of Europe's gas via Ukraine. Brussels had announced intentions to take part in the modernization of Ukraine's gas transit system.

Naftogaz said it would pay on time and in full for October's deliveries.