In the last week, a handful of popular anti-Putin Twitter accounts have been spontaneously shut down by the social media company’s censors. At least five have been suspended so far.

The most popular Putin parody was @DarthPutinKGB, which had more than 50,000 followers,” reports The Telegraph. “On Tuesday afternoon, tweets from the account were no longer visible, with a brief note explaining ‘This account has been suspended.’”

The suspensions of the Kremlin-critical accounts were first reported by fellow users on Twitter:

Twitter has refused to specify why the accounts were shut down by the company’s censors, despite the inherently political nature of the suspensions. "We do not comment on individual accounts, for privacy and security reasons,” stated a Twitter spokesman, directing all inquiries to the company’s official user guidelines.

However, that didn’t stop Twitter users from voicing their outrage about the controversial crackdown.

While Vladimir Putin has instituted aggressive censorship policies in his own country of Russia, the dictator’s reach has rarely extended to private Western businesses. It’s unclear if Putin himself has had any involvement or communication with Twitter corporate, but the social media giant is now under intense scrutiny by free speech advocates who have accused the company of becoming a propaganda arm of the Kremlin.