NSA whistleblower Edward Snowden has accused the US administration of "political interference" for firing FBI Director James Comey while Julian Assange has invited the latter to work for WikiLeaks.

Comey was fired on Tuesday, days after he testified before a Senate Judiciary Committee about the investigation into alleged Russian interference in the 2016 presidential election.

"Set aside politics: every American should condemn such political interference in the Bureau's work," Snowden tweeted.