President Donald Trump said he was displeased with the Federal Reserve raising interest rates in response to a strengthening U.S. economy.

“I don’t necessarily agree with it, because he’s raising interest rates … I don’t necessarily agree with it, and I must tell you I don’t, I’m not thrilled,” Trump said in an interview with CNBC.

He called Federal Reserve chairman Jerome Powell “a very good man” but signaled his disagreement with the decision to raise interest rates.

Business media figures immediatly expressed alarm, noting that Trump was breaking presidential tradition by publicly revealing his opinion about the Federal Reserve, threatening the independence of the institution.

“Every time you go up they want to raise rates again,” Trump complained.

He pointed out that China and the European Union continued to grow and enjoy a lower currency, suggesting it was giving them an economic advantage.

Despite his frustrations, Trump said that he would let the Federal Reserve remain independent.

“I don’t really — I am not happy about it,” he said. “But at the same time I’m letting them do what they feel is best.”