Governments of eight central and eastern European countries have raised objections to Russia’s Nord Stream-2 gas pipeline project in a letter addressed to European Commission’s President, Jean-Claude Juncker, on the grounds that it may be “potentially destabilizing geopolitical consequences,” according to Reuters. The Nord Stream-2 project, which is currently under preparation, aims at doubling current gas supplies shipped directly from Russia to Germany across the Baltic Sea to the level of 110bcm/year, while circumventing the central and eastern European nations threatening their energy security.

The letter was signed by the leaders of Latvia, Estonia, Lithuania, Hungary, Poland, Romania, Slovakia, and the Czech Republic. Croatia has also signed the letter, anonymous EU sources told Reuters, but the country’s government did not immediately confirm the information.

The leaders expressed concern that the project might strongly affect gas market development and gas transit dynamics in the region. As EU relies on Russia for more than 30% of its total gas supplies, it is Ukrainian pipelines that currently represent the transit route for about 50% of all gas that Russia’s Gazprom sells to the EU.

Ukraine and Russia have recently entered into a conflict since street protests forced out Ukraine’s Moscow-backed president in 2014, followed by Russian annexation of Ukraine’s Crimea region. Moscow continuously supports Ukrainian separatists in the east of the country. The conflict has triggered EU sanctions against Russia and increased anxiety among eastern European nations that Moscow may arbitrarily halt gas supplies via Ukraine in the future and thus leave the central and eastern EU countries without energy sources. Hence, Russia’s gas export has become intensely political.

The Nord Stream-2 pipeline scheme had previously generated heated debates at an EU summit last December, followed up with a first letter sent to the European Commission representatives. On his side, European Council Head, Donald Tusk, a Polish politician, had said then it would be up to the Commission to make a final decision on the legality of the Nord Stream-2 project.

The contract for Russian gas transit through Ukraine to Europe was signed by Gazprom and Ukraine’s Naftogaz in 2009 and expires at the end of 2019. Russian Energy Minister, Aleksander Novak, earlier said that Russia had no plans to abandon gas transit through Ukraine, but was not going to extend the contract on unfavorable conditions. The announcement came as Naftogaz (Ukraine) radically increased transit fees for Gazprom. The two gas companies have filed legal complaints over the contracts for gas supplies and transit since they could not have reached a compromise.