The EU has started legal action against Russian energy giant Gazprom, the bloc's competition chief said on Thursday (3 October).

Speaking at an event to mark European Competition Day in Lithuanian capital Vilnius, EU competition commissioner Joaquin Almunia confirmed that the EU executive had started to draw up a formal charge sheet against the firm.

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He refused to speculate on the time frame of the case, which comes against a backdrop of increased tensions between Russia and the EU over Russian pressure on former Soviet states to eschew EU integration.

"It would be premature to anticipate when the next steps would be taken in this investigation, but we have now moved to the phase of preparing a statement of objections," he said.

But a statement published by the Lithuanian government the same day revealed that the commission would complete its work by spring 2014.

Almunia confirmed that the investigation covers Bulgaria, the Czech republic, Estonia, Hungary, Latvia, Lithuania and Poland.

The development is a significant victory for Lithuania, whose complaint on alleged Gazprom price-gouging prompted the launch of the EU enquiry back in 2011.

The Baltic country has made EU energy policy in general key priority of its six month presidency of the EU.

Its Prime Minister, Algirdas Butkevicius, on Thursday described the EU move as being “of crucial importance” to his country.

The anti-Gazprom claims say it is abusing its dominant market position to demand extortionate prices for gas and preventing countries from diversifying their energy supply.

Lithuania says it pays 35 percent more than Germany for gas under its contract with Gazprom.

For its part, the energy giant has said that it has received no formal communication from the EU executive and has made no attempt to offer concessions in a bid to reach a settlement.

Under EU rules, Gazprom, whose turnover hit 4.76 trillion roubles (€109 billion) in 2012, could face a fine of up to 10 percent of their annual revenues.

The €1.1 billion fine levied on software giant Intel in 2009 is, as yet, the largest single antitrust fine imposed by the EU.