MOSCOW - Hundreds of Signal users in Russia on Friday reported glitches with the messenger app, a secure communications tool used by up to a million Russians to encrypt messages and conversations.

Internet service monitoring sites showed more than 1,500 complaints about Signal, mostly from users in Moscow and St Petersburg. Users reported, however, that it was working normally when accessed via a VPN or used in the built-in censorship bypass mode.

"This indicates precisely a blocking of the messenger in Russia and not a technical problem on the Signal side," Mikhail Klimarev, author of the Telegram channel "For Telecom", told Reuters.

Signal did not immediately reply to a request for comment. Russian internet watchdog Roskomnadzor also did not immediately respond to a request for comment.

It was also impossible to register a new account on Signal without a VPN, three people from Moscow and the Krasnodar region told Reuters. When entering a mobile number, the service displayed the message "Server Error".

Klimarev said it would be the first attempt to block the messenger in Russia.

  - Reuters