The letter was signed by the prime ministers of Estonia, Latvia, the Czech Republic, Hungary, Romania, and Slovakia as well as the president of Lithuania.

The planned second gas pipeline under the Baltic Sea linking Russia and Germany was not a commercial project, but a geopolitical one, aimed at harming Ukraine and dividing Europe, Lithuanian President Dalia Grybauskaite said.

"It is highly regrettable that some of our larger EU partners are trying to argue that this is just a private commercial project. It is absolutely clear to all of us that energy projects of this scale are geopolitical, and their goals are geopolitical. This is why eight leaders, including myself, have signed this letter, so that the European Commission cannot ignore and turn a blind eye to further large-scale attempts at dividing Europe and pushing it back into dependence on a single source, that is, the Russian energy source," Grybauskaite said to LRT Radio on Thursday morning.

According to Grybauskaite, the pipeline poses a threat to the EU's solidarity and energy security. It was not an economic project, because the existing Nord Stream pipeline was operating at just over 50% of its capacity.

"Nord Stream 1 is operated at slightly more than 50%, which raises a lot of questions. Practically, half of it is not being used. So, what is the purpose of having Nord Stream 2? The purpose is very clear. First, it would bypass Ukraine, so that it would no longer be a transit country and things would be even more difficult for it. What we see is a purely politicized project directed against Ukraine and some eastern EU countries. Also, there is apparently a divide-and-rule policy or a divide-and-influence policy," she said.

The Russian gas giant Gazprom and five European companies signed an agreement last year on a joint venture, called the New European Pipeline, for a €10bn expansion of the Nord Stream pipeline. The plan is to build two additional strings of Nord Stream by late 2019 to double the pipeline's annual capacity to 110bn cubic meters.