CNN severed ties with Jeffrey Lord on Thursday, hours after he ignited controversy by tweeting the words “Sieg Heil!” at a prominent liberal activist.

“Nazi salutes are indefensible,” a CNN spokesperson said in a statement. “Jeffrey Lord is no longer with the network.”

Lord, a columnist for The American Spectator, has been harshly critical of the activist he tweeted at, Angelo Carusone, and the liberal group of which Carusone is president, Media Matters for America.