Former National Security Agency contractor Edward Snowden on Thursday lamented Julian Assange's arrest by authorities outside the Ecuadorian embassy in London, calling the event "a dark moment" for freedom.

Snowden, 35, who lives in Moscow, Russia under political asylum after he leaked classified information to reporters, made a brief statement via Twitter about the Assange arrest. He linked to a video showing officials entering the embassy and removing a startled-looking Assange.

[ WATCH: WikiLeaks founder Julian Assange dragged out of Ecuadorian Embassy in London by police]

"Images of Ecuador's ambassador inviting the UK's secret police into the embassy to drag a publisher of--like it or not--award-winning journalism out of the building are going to end up in the history books. Assange's critics may cheer, but this is a dark moment for press freedom," Snowden said.

Snowden has been charged by the Department of Justice on two counts of violating the Espionage Act of 1917 and one charge of stealing property of the U.S. federal government. The Russian government has continuously extended his asylum status for one-year periods since 2013.

Following the Assange arrest, a spokesman for Russian President Vladimir Putin said Putin wants the authorities to respect Assange's basic rights as they move forward with a prosecution.

“We of course hope that all of his rights will be observed," Putin spokesman Dmitry Peskov told reporters on Thursday.