Edward Snowden has slammed the decision by President Donald Trump to fire FBI Director James Comey Tuesday.

“This FBI Director has sought to jail me on account of my political activities,” Snowden tweeted. “If I can oppose his firing so can you.”

In an earlier tweet, Snowden wrote that “every American should condemn such political interference in the Bureau’s work.”

Snowden, the former CIA employee who exposed global surveillance programs run by the National Security Agency and others, has previously railed against Trump’s approach to intelligence gathering.

In March, the whistleblower — who was granted asylum in Russia and is currently living in Moscow — rubbished accusations that former President Obama had “tapped” Trump Tower. “If Donald Trump or anyone else wants us to take this seriously, they have to show evidence,” Snowden told The Intercept. “And the fact that they have not despite the severity of this allegation means that they’re trying to make political hay — I suspect — out of something that affects all of us, which is that mass surveillance is making all of us vulnerable.”

Trump, in turn, has in the past threatened to execute Snowden. “I think he’s a terrible traitor, and you know what we used to do in the good old days when we were a strong country? You know what we used to do to traitors, right?,” he said, during an appearance on Fox and Friends in 2013.

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Joseph Hincks at joseph.hincks@time.com.