"The risks that Estonia and other countries repeatedly emphasized in connection with the Nord Stream 1 project sounded like an exaggeration to many countries of Europe five years ago. Now they are very real. For the time being, the black scenario has materialized in Ukraine only, but it may spread," Herkel said in a letter written in German and addressed to German Chancellor Angela Merkel, the German government, and members of the Bundestag.

Reminding them that the Russian gas giant Gazprom holds a 51% stake in the pipeline, Herkel pointed out that Gazprom was controlled by the Kremlin and one of the companies on the EU's list of sanctions against Russia. The company is an important part of Vladimir Putin's vertical of power, a source of resources and levers of power.

“The implementation of a large-scale energy project in collaboration with Gazprom means a violation of the principle of solidarity and is rendering the sanctions pointless,” Herkel wrote.

Herkel also said that the implementation of the project would cause a serious economic crisis in Ukraine, a country that has suffered as a result of Russian meddling and aggression, as the export of gas via Ukraine to Eastern and Central Europe was an important source of revenue for the country. "Bringing Ukraine to its knees serves the interests of the Kremlin. We are resolutely against failing Ukraine," Herkel said.

Herkel said the German government had not demonstrated an understanding of the dangers of the Nord Stream 2 project and the risks that came with it. He expressed hope that the German leadership would consider the bigger picture, and said that projects like this needed to be halted until Russia respected international law.