Russian energy giant Gazprom has cut gas supplies to Europe via Ukraine to around two-thirds of its normal flow, which will disrupt supplies to Europe, Ukrainian state gas company Naftogaz spokesman Valentin Zemlyanski said on Tuesday.

"They have reduced deliveries to 92 million cubic meters per 24 hours compared to the promised 221 million cubic meters without explanation. We do not understand how we will deliver gas to Europe," said Zemlyanski.

"This means that in a few hours Europe will face a problem with gas supplies," he added.

The nearly 60-percent reduction came a day after Russian Prime Minister Vladimir Putin ordered Gazprom to start cutting supplies bound for Europe via Ukraine in retaliation for Ukraine's alleged theft of Russian gas.

Ukraine denied that it was siphoning off gas and has accused Russia of being behind the current gas crisis.

A number of European Union countries have reported drops in supplies after Russia's state gas monopoly Gazprom cut off supplies to Ukraine last Thursday after the two sides failed to agree on terms for a 2009 contract amid conflicts over a new price and gas transit fees.

Around a quarter of the gas used in the EU -- more than 40 percent of the bloc's imports -- comes from Russia, and Ukraine sits on the main transit route for gas exports, accounting for 80 percent of the continent's gas supply from Russia.

In 2006, a dispute over gas prices between Kiev and Moscow sent jitters among European customers after Gazprom cut all gas supplies to Ukraine.

(Xinhua News Agency January 6, 2009)