All Russian gas supplies to Europe through Ukraine were cut off on Wednesday as a gas row between Russia and Ukraine escalated, prompting the European Union (EU) to send monitors to check the gas flow.

"We really hope that the Russians put the gas in the ... Ukrainian network and that Ukrainians do not interrupt the gas from Russia coming to the European Union," European Commission President Jose Manuel Barroso told reporters in Prague after a meeting with the Czech EU presidency.

"We have received assurances, both from (Russian) Prime Minister Putin and (Ukrainian) Prime Minister Tymoshenko, that they both accept international monitors to verify on the ground that this is really working," he added.

Russia shut off all gas supplies to Europe via Ukraine earlier on Wednesday, accusing Kiev of "stealing" the gas in transit, but Ukraine's state-owned gas company Naftogaz denied and blamed Russia for the spreading shortage of gas in many European countries.

Russian Prime Minister Vladimir Putin said his country will only resume gas supplies when international monitors are in place.

Caught up in the gas row between Russia and Ukraine and hit by freezing weather, several Eastern European countries were faced with a serious gas crisis, with factories shut down, schools closed and thousands of people left without gas for heating.

As a country which virtually has no other gas supply source except Russia, Bulgaria had already declared a state of crisis. Seventy-two schools in Bulgaria, reliant on gas-powered heating, were closed on Wednesday.

The Bulgarian government said it would receive part of the five billion euros (US$6.8 billion) that the EU had set aside to tackle the financial crisis in order to deal with the effects of the cutoff of gas supplies.

Croatia also declared a state of emergency, while Hungary limited gas supplies to industries, causing a Hungarian unit of Japanese carmaker Suzuki to halt production.

The Slovak-based factories of French carmaker PSA Peugeot and Korean Kia Motors also said they would stop production on Thursday because gas supplies had been cut off.

The International Energy Agency warned that Bulgaria, Romania, Greece and Turkey would have difficulty providing electricity and heating if the cold weather and gas disruptions continued next week.

Faced with a severe threat of gas shortage, the EU is adjusting its position of being reluctant to intervene in the Russian-Ukraine gas row.

Czech Prime Minister Mirek Topolanek said both Russian gas monopoly Gazprom and Ukraine's Naftogaz and their government representatives had been invited for a meeting in Brussels on Thursday, which will set technical conditions of a monitoring mission.

"If this is agreed, nothing will stand in the way for transit supplies to be restored ... That does not mean that success is 100 percent assured," Topolanek said.

Earlier in the day, Commission President Barroso talked on the phone with both Putin and Tymoshenko, urging the prime ministers to restore full gas supplies to the EU immediately.

"It is unacceptable that the EU's gas supply security is being taken hostage to negotiations between Russia and Ukraine," Barroso said. "Now the two countries' reputation as reliable partners to the EU is at stake."

Topolanek warned that the EU will intervene if Russia and Ukraine fail to solve their dispute by Thursday.

"There is a political dimension to this problem," Topolanek said in Prague. "Tomorrow is a key day. If supplies are not restored tomorrow, then we will have to see a stronger EU intervention."

Russia cut off gas supplies to Ukraine on Jan. 1 after the two countries failed to reach an agreement on gas prices for 2009, immediately resulting in disruptions of transit supplies to EU member states.

About a quarter of the gas used in the EU, or more than 40 percent of the bloc's imports, comes from Russia.

Ukraine sits on the main transit route for Russia's gas exports, with about 80 percent of Russian gas supplied to the EU passing through its territory.

A similar dispute over gas prices between Kiev and Moscow erupted in 2006 when Gazprom cut all gas supplies to Ukraine, raising deep concerns among European customers.

(Xinhua News Agency January 8, 2009)