WASHINGTON — President Trump has stepped up his attacks on Federal Reserve Chairman Jerome Powell, saying he “maybe” regrets appointing him to the post and demurring when asked under what circumstances he would fire the central bank chief.

Trump told The Wall Street Journal in an interview Tuesday that he was intentionally sending a direct message to Powell that he wanted lower interest rates, even as he acknowledged that the central bank is an independent entity.

Trump said in the interview that Powell “almost looks like he’s happy raising interest rates” and that is “too early to tell, but maybe” he regrets appointing him.

Trump sidestepped a question on what circumstances would lead him to remove Powell. “I don’t know,” Trump said. That contrasted with his response to a similar question Oct. 11, when he answered, “I’m not going to fire him.”

The law governing the Federal Reserve allows its governors to be “removed for cause by the president,” but it doesn’t specify what “cause” means.

Trump has repeatedly criticized the Fed for rate increases, ratcheting up his rhetoric in recent weeks. Trump last week called the Fed his “biggest threat” and blamed it for stock market selloffs during the past month. Earlier in the month he slammed the central bank as “out of control” and said it was “going loco.”

The Fed has raised its benchmark policy rate three times this year, by a quarter-percentage point on each occasion, bringing to six the number of increases since Trump was inaugurated. The target range for the federal funds rate, currently at 2 percent to 2.25 percent, is low by historical standards. When factoring in inflation, the rate on short-term borrowing is near zero percent.

Trump’s criticisms mark a departure from the practices of his recent predecessors. Presidents for more than two decades avoided public comments on Fed policy as a way of demonstrating respect for the institution’s independence.