* Lithuania seeks compensation from Gazprom
* Part of long-running dispute
VILNIUS, Oct 3 (Reuters) - Lithuania is seeking 5 billion litas ($1.87 billion) from Gazprom at an international arbitration court, part of a tit-for-tat dispute with the Russian gas giant as the Baltic state pressures it for cheaper prices.
"The dispute is connected with a 5-billion-litas overpayment for Gazprom gas, which was supplied to Lithuania under certain contracts," the Energy Ministry said in a statement, which was released as Lithuania heads to elections in two weeks.
The ministry said it was taking its case to an arbitration court in Stockholm.
The relationship between Moscow and the European Union has been strained after the European Commission opened an investigation into suspected anti-competitive market practices by Gazprom.
The probe is focused on suspicions Gazprom was hindering the free flow of gas across the EU's 27 countries, preventing supply diversification and imposing unfair prices on its customers by linking the price of gas to oil prices.
Lithuania said Gazprom raised prices between 2004 and 2012 in violation of the terms of the privatisation of gas company Lietuvos Dujos, in which Gazprom and Germany's E.ON have 37.1 percent and 38.9 percent stakes, respectively.
"We have tried to convince them with very clear arguments, that Gazprom could correct the price without arbitration, but we didn't receive it," Prime Minister Andrius Kubilius, who is facing defeat in the election to centre-left parties, told reporters.
Energy Minister Arvydas Sekmokas said the court proceedings could take between 18 months to two years.
The Energy Ministry said Gazprom had also twice applied to the Stockholm court after the Lithuanian government started to investigate Lietuvos Dujos, but that the court in July rejected Gazprom's compensation demand.
At the same time, the court had said Lithuania could not take claims over pricing to local courts but had to take them to Stockholm, which was what the ministry was now doing.
Lithuania has clashed several times with Gazprom over prices and over its decision to split Lietuvos Dujos into a gas transport and gas sales company, part of European Union plans to liberalise the gas market.
($1 = 2.6694 Lithuanian litas)
(Reporting by Andrius Sytas, writing by Patrick Lannin; Editing by Louise Heavens)
Keywords: LITHUANIA GAZPROM/