MOSCOW -
Western Europe is watching warily as Russia and Ukraine are locked in a natural gas dispute that has reduced the supply to Ukraine by at least half since the beginning of the week.
After Russia's state-controlled natural gas monopoly announced the second supply cut in two days Tuesday, Ukraine's natural gas company said there are no immediate plans to divert Europe-bound gas to Ukrainian customers, but held out the possibility it could do so if reserves run low. Much of the Russian gas consumed in Europe comes in pipelines crossing Ukraine.
The Russian monopoly, OAO Gazprom, is demanding Ukraine sign documents resolving a $600 million debt dispute and enabling further gas deliveries. On Monday, it cut shipments by 25 percent.
Gazprom spokesman Sergei Kupriyanov announced another 25 percent cut Tuesday evening and held out the possibility of more.
The European Union "looks to the parties to make every effort to find a rapid and durable solution to their disagreement. In addition, we look to both parties to ensure that gas supplies to the EU remain unaffected," EU Energy Commissioner Andris Piebalgs said in a statement.
A spokesman for Naftogaz, Ukraine's natural gas company, said earlier Tuesday that the company could begin diverting transit gas if a second cut were imposed. But after Kupriyanov's announcement, another spokesman said such a move was not in the immediate offing because of warm weather and substantial reserves.
"We will do that if our energy security is threatened. At the moment it is not," Valentyn Zemlyansky told The Associated Press in Kiev.
Siphoning off Europe-bound gas would be a risky move for Ukraine, whose government is seeking closer ties with the West while trying to move out of Moscow's sphere of influence.
Gazprom portrays the cutoffs as a straightforward commercial dispute, but it has considerable political resonance.
Gazprom's chairman is Russian President-elect Dmitry Medvedev, and critics accuse the Kremlin of using Gazprom as an instrument of pressure. Russia has watched with irritation as Ukrainian President Viktor Yushchenko pushes for membership in NATO and the EU.
In a telephone conversation with Yushchenko on Tuesday, Medvedev urged Kiev to pay the debt, Medvedev's office said.
Medvedev told Yushchenko that Russia "expects an intensification of Kiev's efforts for the swiftest resolution to the problem of debt for gas that has been delivered," Medvedev's office said.
"We have little reliable information on who owes what to whom. It is thus unclear whether this is a commercial dispute or something more," said Steven Pifer, a former U.S. ambassador to Ukraine who now is an analyst at the Center for Strategic and International Studies.
Only about one-quarter of the gas imported by Ukraine is of Russian origin; the rest comes from Turkmenistan and Kazakhstan in pipelines controlled by Gazprom. Naftogaz said that by going ahead with the threatened reduction, Gazprom would be cutting the Central Asian gas as well as Russian-origin gas - a move that "grossly violates technical agreements between the two companies."
Gazprom last month threatened to cut supplies to Ukraine over a $1.5 billion debt dispute, timed to coincide with Yushchenko's visit to Moscow. That cutoff was avoided by a last-minute agreement between Yushchenko and President Vladimir Putin.
But documents formalizing that agreement have not been signed by Ukraine's natural gas company, and Gazprom says Ukraine still owes $600 million for gas delivered this year.
Zemlyansky said the current dispute centered on the controversial middlemen companies that are used in the gas trade. He did not elaborate.
Critics say the laborious arrangement is essentially a mechanism for siphoning money into private pockets, and Ukrainian Prime Minister Yulia Tymoshenko has called for direct dealings with Gazprom.
Both the Central Asian gas and the Russian-origin gas that Ukraine imports is purchased from RosUkrEnergo, an intermediary company half-owned by Gazprom and half by two Ukrainian businessmen. The gas in turn is sold to UkrGazEnergo - jointly owned by Naftogaz and RosUkrEnergo - which then supplies Naftogaz.
The agreement reached last month by Putin and Yushchenko foresaw the elimination of the intermediaries, but Gazprom President Alexei Miller later said two other middlemen operations would be created, each to be half-owned by Gazprom and Naftogaz. Tymoshenko has criticized the agreement.
