While Russia and Ukraine find new ways to disagree about restoring gas supplies to Europe mothers and their newborn infants shiver as they crowd into the one maternity ward left with any heating in the main hospital in Sofia, Bulgaria, the Times of London reported.

Shops in the Bulgarian capital have run out of electric heaters and families scoured the city for help to keep warm as temperatures fell to minus -4F.

The former Soviet nation is almost totally reliant on natural gas from Russia but here, as in the other European countries cut off during Moscow’s dispute with Kiev, people have begun to question the wisdom of dependence on its one-time protector, the Times of London reported.

A dozen nations denied gas since Wednesday were warned Friday that even when the taps were turned back on by Gazprom, the Russian state-owned fuel company, it could take three days for supplies to reach consumers.

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Russian and European Union officials have signed a deal regarding the deployment of EU officials to monitor Russian gas shipments through Ukraine.

But the deal — a key condition for the resumption of Russian gas supplies to freezing Europe — must still be signed by Ukraine to come into force.

Russian and EU officials approved it following Saturday's talks between Russia's Prime Minister Vladimir Putin and visiting Czech Prime Minister Mirek Topolanek.

Russian Prime Minister Vladimir Putin insisted Saturday that a written agreement on the deployment of EU monitors to Ukraine must be signed before Russia resumes gas shipments to a freezing Europe.

Putin promised to return gas flow to Europe once EU monitoring is launched.

Putin told Czech Prime Minister Mirek Topolanek that the deal must spell out details of the monitoring team's operation. Topolanek, whose country holds the rotating European Union presidency, met with Putin after holding talks in Ukraine on Friday night.

The EU experts arrived in Ukraine on Friday prepared to monitor the flow of gas and act as referees in a bitter economic battle between the two former Soviet states.

But there were no gas shipments for EU monitors to track Saturday, as Russian and Ukrainian continued bickering over details of the monitoring pact.

"I hope you will succeed in persuading our Ukrainian partners to sign the documents which would set up a mechanism for transit of our gas across Ukraine," Putin said at his suburban residence outside Moscow at the start of his talks with Topolanek.

The Russian natural gas giant Gazprom halted the shipment of gas intended for Ukraine Jan. 1 after negotiations over a new gas contract broke down.

Russia then accused Ukraine of siphoning its gas intended for Europe, and finally turned off the taps on all gas shipped through Ukraine on Wednesday, ending or reducing gas supplies to more than a dozen European nations as winter turned bitterly cold across the region.

A commercial dispute over gas transit and prices triggered the current crisis, but relations between the two ex-Soviet neighbors deteriorated after the 2004 Orange Revolution in Ukraine led to the election of a pro-Western government in Kiev. Russia has been keen to restore its clout in the former Soviet sphere.

Russia — which supplies about one-quarter of the EU's gas, most of it shipped through Ukraine — says the EU monitors are needed to prevent what it described as Ukraine's theft of supplies meant for Europe, a charge Kiev hotly denies.

Ukraine says the deal proposed by Russia will give Russian officials too much access to the Ukrainian gas transit system.

"The aim of the protocol is basically to subjugate the Ukrainian side to Gazprom," Ukraine's Deputy Foreign Minister Kostyantyn Yeliseyev told reporters Saturday. "This essentially paves the way for the expropriation of the Ukrainian gas transport system by the Russian side."

Volodymyr Trikolich — deputy chief of Ukraine's state gas company, Naftogaz — also claimed that Gazprom wanted to gain access to Ukrainian gas pumping stations and to conduct a full review of the country's entire transport system, including its storage facilities, while not giving Ukraine equal access to Gazprom's system.

Russian Foreign Ministry spokesman Andrei Nesterenko rejected those claims, saying that Moscow's "only aim is to ensure a transparent transit of gas across Ukraine." He said in a statement that Ukraine dragging its feet on the deal means "it has something to hide."

EU governments have criticized both Russia and Ukraine for the crisis, saying it was unacceptable to see homes unheated, businesses closed and schools shut down during winter because of the commercial squabble.

"It has gone so far now that it's not an issue who is to blame for that," Topolanek told Putin.

Russia in the past has sold gas to Ukraine and some other former Soviet neighbors at prices significantly lower than those it charges Europe.

Russian President Dmitry Medvedev said Friday that Ukraine should pay a European price for the Russian gas. Last year, Russia charged Ukraine $179.50 per 1,000 cubic meters, about half what it charged its European customers.

Gazprom is currently demanding $450 per 1,000 cubic meters, a price that could hit Ukraine's consumers and heavy industry hard at a time when the country is suffering a sharp economic downturn.

The disruption of Russian gas supplies comes during a harsh winter. At least 11 people have frozen to death this week in Europe, including 10 in Poland, where temperatures have sunk to minus 13 F.

Fifteen countries — Austria, Bulgaria, Bosnia, Croatia, the Czech Republic, France, Greece, Hungary, Italy, Macedonia, Romania, Serbia, Slovakia, Slovenia and Turkey — said their Russian supplies ceased Wednesday. Germany and Poland also reported substantial drops in supplies.

Ukraine said it would supply Bulgaria, where thousands of homes are without heating and factories have been shut, with 2 million cubic meters of gas daily beginning Saturday. Bulgaria's average daily consumption before the crisis was some 8 million cubic meters. Ukraine said it also will ship 1.5 million cubic meters of gas a day to neighboring Moldova.

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The Associated Press contributed to this report.