Edward Snowden has laid into the Russian government for banning the use of virtual private networks (VPNs) and other tools that people can use to circumvent censorship and surveillance.
Russian president Vladimir Putin signed the law on Sunday, prompting a Twitter tirade from Snowden, the US National Security Agency (NSA) whistleblower who has been sheltering in Moscow since 2013.
Snowden called the decision a "tragedy of policy" that would make Russia "both less safe and less free". He also linked the government's move to China's crackdown on VPN technology, which led Apple to pull dozens of VPN apps from its Chinese App Store over the weekend.
"Whether enacted by China, Russia, or anyone else, we must be clear this is not a reasonable 'regulation,' but a violation of human rights," Snowden wrote, arguing that: "If the next generation is to enjoy the online liberties ours did, innocuous traffic must become truly indistinguishable from the sensitive."
He also appeared to urge tech industry workers to push back against the anti-VPN trend.
Snowden is these days the president of the Freedom of the Press Foundation. In line with his 2013 decision to expose the NSA's mass-surveillance activities, he has long been an advocate of individuals being able to protect their communications and online activities.
However, he has previously warned against people relying too much on VPNs, because their operators may be vulnerable to hacks or subpoenas that could expose users.
The former NSA contractor originally fled from the US to Hong Kong, where he famously started working with newspapers to expose the agency's activities.
Then, while apparently trying to fly to Latin America, Snowden found himself stranded at a Moscow airport because the US had cancelled his passport. The Russians granted him asylum, which was extended for "a couple more years" in January this year.
During his stay there, Snowden has occasionally voiced strong criticism of Russia's surveillance policies.
In mid-2016, when the Russian government introduced a data-retention law and forced communications providers to help decrypt people's messages, the American said the legislation was "an unworkable, unjustifiable violation of rights that should never have been signed".
In 2014, he also denounced the so-called Blogger's Law, which imposed restrictions on what bloggers can write.
The latest law, banning VPNs, will come into effect in November this year. It is mainly intended to stop Russians viewing websites that are on the official state blacklist.