President Donald Trump criticized former Secretary of State Rex Tillerson Thursday after a report revealed Tillerson believed Trump was unprepared for a meeting with Russian President Vladimir Putin.

“Rex Tillerson, a man who is ‘dumb as a rock’ and totally ill-prepared and ill-equipped to be Secretary of State, made up a story (he got fired) that I was out-prepared by Vladimir Putin at a meeting in Hamburg, Germany,” Trump tweeted Thursday. “I don’t think Putin would agree. Look how the U.S. is doing!”

Rex Tillerson, a man who is “dumb as a rock” and totally ill prepared and ill equipped to be Secretary of State, made up a story (he got fired) that I was out-prepared by Vladimir Putin at a meeting in Hamburg, Germany. I don’t think Putin would agree. Look how the U.S. is doing!

— Donald J. Trump (@realDonaldTrump) May 23, 2019

Tillerson told lawmakers on the House Foreign Affairs Committee that Trump was out-prepared for a key 2017 meeting with Putin at the G20 summit in Germany, according to a report published by The Washington Post Wednesday night. (RELATED: Russian President Putin Makes Plea To Trump At Helsinki)

“We spent a lot of time in the conversation talking about how Putin seized every opportunity to push what he wanted,” a Committee aid told the Post. “There was a discrepancy in preparation, and it created an unequal footing.”

Tillerson also reportedly told the committee that while he and Trump shared a “common goal,” they had a different set of values, though he reportedly said he “cannot” describe those values.

Trump fired Tillerson in March 2018 and replaced him with then-CIA director Mike Pompeo.

Trump and Tillerson had a tenuous relationship during their partnership, and the president has frequently taken jabs at his former secretary of state over the past year, tweeting in Dec. 2018, that Tillerson is “dumb as a rock,” and “lazy as hell.”