Russia has demanded that 13 foreign technology companies be officially represented on Russian soil by the end of 2021, but has given few details on what it requires in practice, targeting some firms that already have Russian offices.

President Vladimir Putin signed a law, effective from July 1, which obliges foreign social media giants to open offices in Russia, part of a wider campaign by Moscow to exert greater control over Big Tech, Reuters reported from Moscow.

State communications regulator Roskomnadzor published late on Monday a list of foreign firms with more than 500,000 daily users that it said must comply with the law. Firms that violate the legislation could face penalties such as advertising bans.

Companies named include Alphabet’s Google, Facebook, Twitter, TikTok and messaging app Telegram, all of which Russia has fined this year for failing to delete content it deems illegal.

Apple, which Russia has targeted for alleged abuse of its dominant position in the mobile applications market, was also on the list.

None of the companies responded immediately to requests for comment.

Lack of Clarity:Exactly what representation the companies need to have is unclear, said Karen Kazaryan, head of analysis firm Internet Research Institute.

“There is no explanation in the law, no clarification as to what the legal form of the organisation’s representation should be,” Kazaryan told Reuters on Tuesday.

Roskomnadzor, when asked for more clarity, referred Reuters to its statement.

In addition to having representation in Russia, firms must open an account on the regulator’s website and have a feedback form for interacting with Russian users, Roskomnadzor said.

“Foreign entities are required to limit access to information that violates Russian legislation,” said Roskomnadzor, without providing further details.