BRUSSELS, Jan. 13 (Xinhua) -- Russia restarted pumping gas into Ukraine's southern pipeline early on Tuesday, but Europe said it hasn't seen any significant rise in gas flow.
European Commission President Jose Manuel Barroso spoke by phone to Russian Prime Minister Vladimir Putin, expressing disappointment over the lack of natural gas flowing to Europe.
EU monitors on the ground reported that only very little gas is flowing through the pipelines. Barroso voiced his "disappointment with both the level of gas flowing to Europe" and the lack of access "of our monitors to dispatch centers," said his aide.
According to Russian gas giant Gazprom, international observers monitoring the gas flow in Ukraine's pipelines have said that Kievis blocking the transit of Russian gas to Europe.
"The international monitoring commission's observers in Kiev signed a report which testifies to no pumping of Russian gas through Ukraine's transit pipelines to Europe, while the pressure in the pipeline at the border with Ukraine is 70 atmosphere," Gazprom said in a statement.
Meanwhile, Ukraine accused Russia of trying to discredit it by sending natural gas bound for Europe on a technically "unacceptable" transit route over Ukraine's pipeline system.
"Russia shipped natural gas along a route that would require Ukraine to cut domestic consumers out before it can deliver gas to the Balkans," Ukrainian energy adviser Bohdan Sokolovski told reporters.
He said a gas entry point on the Russian border and a gas pumping station near the Romanian border where Russia wants its gas delivered is not linked by an export pipeline. That means Ukraine has to cut service to its eastern industrial regions first.
Moscow cut off gas supplies to Ukraine on Jan. 1 after the two sides failed to reach a new deal for 2009 and resolve differences over payments due.
As the tensions between the two built up, Russia shut off all gas supplies to Europe via Ukraine on Jan. 7, accusing Ukraine of stealing gas intended for Europe.
Countries from Turkey to the Baltics were greatly affected by the supply cut as Europe experienced an unusually cold winter.
Bulgaria and Slovakia, two of the worst hit EU countries, were sending their prime ministers to Moscow in hopes for an early end to the gas row.
Bulgaria's Sergei Stanishev and Slovakia's Robert Fico will visit Moscow on Wednesday, Putin confirmed Tuesday.
"I have just spoken to the prime ministers of Bulgaria and Slovakia, and we came to an agreement that tomorrow we are meeting in Moscow in order to look at the current situation," Interfax quoted Putin as saying.
EU countries rely heavily on gas imports and 80 percent of the gas they buy from Russia is shipped through Ukraine.
This is not the first time that EU nations have suffered in the fallout of a Russia-Ukraine gas dispute, with the bitter memory of the 2006 energy crisis still vivid for many Europeans.