Russia has imposed sanctions on more than 30 European, American and Singaporean energy companies in a retaliatory move following Western penalties over Ukraine, a government decree said Wednesday.

The Russian government's list targets 31 companies, most of which belong to the Gazprom Germania group of subsidiaries of Russian energy giant Gazprom.

Germany said in April it was taking control of the German subsidiary of Gazprom.

The sanctions also affect Poland's EuRoPol GAZ S.A., the owner of the Polish part of the Yamal-Europe gas pipeline.

The sanctions include a ban on transactions and the entry into Russian ports of vessels linked to the affected companies.

The German ministry of economy and climate protection said on Wednesday the government was "making the necessary arrangements and preparing for different scenarios."

"The gas crisis team is monitoring the situation closely," the ministry added.

"Currently, the security of supply is guaranteed, it is constantly monitored."

Unprecedented in their scale and speed, Western sanctions against Moscow have ranged from freezing assets to export bans on strategic products like semiconductors and financial sanctions.