Ukraine on Tuesday put in place new sanctions seeking to block Russian media and online networks from operating in the country, including VKontakte, the nation’s most popular social network.

The decision, signed by President Petro Poroshenko, was announced in an updated sanctions list, which included the Russian search giant Yandex, social media sites like Odnoklassniki, and a number of Russian state and private television channels.

The spokesman for the Kremlin described the new sanctions as unfriendly and shortsighted and warned that there could be retaliation.

The sanctions, which target the companies that run the sites, mean they cannot do business in Ukraine, but it is not clear if the country has the legal and technical means to totally block them.