Russia has "attempted to fully block" WhatsApp in the country, the company said, as the Kremlin continues to tighten restrictions on messaging apps.
Meta-owned WhatsApp said the move aims to push more than 100 million of its app users in Russia to a "state-owned surveillance app".
This comes after Russian regulators further curbed access to Telegram, citing a lack of security. Telegram is estimated to have as many users as WhatsApp in Russia.
The Kremlin did not immediately respond to a request for comment from the BBC.
"Trying to isolate over 100 million users from private and secure communication is a backwards step and can only lead to less safety for people in Russia," said WhatsApp in a statement.
