(Bloomberg) — Russia’s attempts to restrict the use of virtual private networks amid a clampdown on the Telegram messaging platform triggered the widespread banking outage seen across the country this week, the service’s billionaire founder Pavel Durov said.

“Telegram was banned in Russia, yet 65 million Russians still use it daily via VPNs,” Durov said Saturday in a post on Telegram. “The government has spent years trying to ban VPNs too. Their blocking attempts just triggered a massive banking failure; cash briefly became the only payment method nationwide yesterday.”

Attempts on Friday to limit VPN use could have sparked the disruption affecting banking apps, The Bell and other Russian media reported, citing industry sources who weren’t identified. The outage may have been caused by an overload in the filtering systems run by Russia’s communications watchdog, according to the reports, with experts warning that major restrictions risk undermining network stability. Russian authorities haven’t commented on the outages.

Separately, payments for Apple Inc.’s app store and other services became unavailable in Russia from April 1, the US company said on its website, without saying why. Earlier, RBC newswire reported that the Digital Development Ministry had asked mobile operators to disable top-ups, which could help limit VPN use.

Moscow has in recent months intensified a crackdown on internet use and applications it doesn’t control, as it presses Russians to adopt a state-run “super-app” called Max, modeled after China’s WeChat. It has restricted platforms including YouTube, WhatsApp and Snapchat and limited access to Telegram. In the past week, authorities have stepped up efforts to curb VPN usage, which Russians use to access blocked content.

Authorities are pushing domestic platforms, from IT companies to e-commerce services, to block users connecting via VPNs, Forbes.ru and RBC Newswire reported this week. Proposals discussed at meetings with Digital Development Minister Maksut Shadayev include charging fees for VPN use if international data traffic exceeds a certain level, and restricting access to those platforms for VPN users from April 15.

Durov, who’s being investigated in Russia for allegedly aiding terrorist activity, compared the situation in his home country to Iran, where similar restrictions prompted widespread adoption of VPNs instead of the intended shift to state-backed messaging apps.

“Welcome back to the Digital Resistance, my Russian brothers and sisters,” said Durov, who has lived in Dubai and France in recent years. “The entire nation is now mobilized to bypass these absurd restrictions,” he wrote, adding that Telegram would continue adapting to make its traffic harder to detect and block.