Mexico’s former president used Twitter to troll President Donald Trump during his first congressional speech.

As Trump addressed Congress on Tuesday, Vicente Fox called on U.S. citizens to “wake up,” “stay united,” “question everything” and “act bravely” in the face of the new White House administration.

Fox, who was Mexico’s president from 2000 to 2006, has famously stated his country would not fund Trump’s proposed southern border wall. He’s repeatedly dropped the F-bomb to highlight his point, and regularly sets the #fuckingwall hashtag trending on Twitter.

So when Trump told Congress that there would be a “great, great wall” on the Mexican border, he didn’t hold back. Fox posted artist Chris Britt’s cartoon of Trump trapped inside a brick wall:

.@realDonaldTrump this is the wall I would pay to get it done as fast as possible. #FuckingWall #JointSession pic.twitter.com/rcnlaCyP9c — Vicente Fox Quesada (@VicenteFoxQue) March 1, 2017

“This is the wall I would pay to get it done as fast as possible,” he wrote. The post has since gone viral.

Fox also had plenty else to say about Trump during the speech. Here’s a sampling below:

.@realDonaldTrump is Condemning hate and evil, then he should start by example and take back his hateful words. #JointSession — Vicente Fox Quesada (@VicenteFoxQue) March 1, 2017

What will America look like after @realDonaldTrump? That's up to you, US citizens, WAKE UP TODAY #JointSession — Vicente Fox Quesada (@VicenteFoxQue) March 1, 2017

This #JointSession is only for @realDonaldTrump to use big boy words. Please US congress don't let this guy get away with his own. — Vicente Fox Quesada (@VicenteFoxQue) March 1, 2017

.@realDonaldTrump wants to stop extremists with walls and war. Go and build the #FuckingWall around you and spare us from your evil. — Vicente Fox Quesada (@VicenteFoxQue) March 1, 2017

US rebuilding will come after @realDonaldTrump. Let's hope he doesn't leave a big mess. AMERICA don't let him bully you. #JointSession — Vicente Fox Quesada (@VicenteFoxQue) March 1, 2017

America is waking up! Stay united, question everything, act bravely. @realDonaldTrump is NOT the nation, the country belong to the people. — Vicente Fox Quesada (@VicenteFoxQue) March 1, 2017