Russia's communications minister, Nikolai Nikiforov, says a court may move to block the Viber messaging app if it follows the example of the Telegram messaging service and refuses to provide encryption keys to the Federal Security Service (FSB).
"If they [the FSB] have problems with acquiring encryption keys, they may turn to court and receive a similar court order," Nikiforov told the media on May 3 when asked whether Viber might suffer the same fate as Telegram.
State media regulator Roskomnadzor on April 16 began enforcing a court ban on Telegram over its refusal to provide the FSB with encryption keys.
Telegram has refused to share data, citing privacy concerns, and promised to keep the app running despite the ban.
The move to block Telegram -- with mixed success -- has deepened concerns that the government is seeking to close avenues for dissent as President Vladimir Putin heads into a new six-year term.
On April 30 and May 1, thousands of people protested in Moscow against the authorities' move to block Telegram.
Viber, a cross-platform instant-messaging app operated by Japan's Rakuten company, is not as popular among Russians as Telegram or the Facebook-owned service WhatsApp.
Nikiforov admitted that implementing the court's order to block Telegram had met obstacles, as it caused major problems in the Russian segment of the Internet.
"There is a court order...and if it is being enforced with varying degrees of success, there must be officials accountable for the implementation of the court's decision," Nikiforov said.
Russian social networks reported numerous disruptions after Roskomnadzor blocked access to IP addresses associated with the clouds of U.S. tech giants Google and Amazon in order to comply with a court order to block Telegram.