President Donald Trump just intensified a war of words with Jamie Dimon, the CEO of the country’s largest bank.

“ ‘The problem with banker Jamie Dimon running for President is that he doesn’t have the aptitude or “smarts” & is a poor public speaker & nervous mess — otherwise he is wonderful. I’ve made a lot of bankers, and others, look much smarter than they are with my great economic policy!’ ”

The president, via Twitter, referred on Thursday to the head of JPMorgan Chase & Co. JPM, -1.62% as “a poor public speaker & nervous mess,” who doesn’t have the “aptitude” to be commander in chief, in an apparent response to Dimon’s comments a day earlier.

On Wednesday, the outspoken JPMorgan chieftain said he could beat Trump in a presidential contest, claiming during an event sponsored by the bank that he was ”smarter” than the 45th U.S. president and equally tough. Dimon later moderated his remarks, emphasizing that he wasn’t officially throwing his hat in the ring for president and adding that he shouldn’t have made his comments.

However, Dimon’s attempt to walk back his comments didn’t appear to be sufficient to stay Trump’s Twitter fingers:

“I get frustrated because I want all sides to come together to help solve big problems,” Dimon said on Wednesday in remarks emailed by a JPMorgan representative.

In the past, Dimon has described himself as a patriot who wants to serve his country but so far has been reluctant about entering the political arena in earnest. “I would love to be president of the United States of America,” he said two years ago, according to a Vanity Fair article.

Shares of JPMorgan were up 0.1% in premarket trade on Thursday and have gained 5.7% so far in 2018, exceeding the performance of banking peers, as of Wednesday’s close of trade.