President Donald Trump ripped Federal Reserve Chair Jerome Powell as a “numbskull” on Thursday as he turned up the heat on the central bank chief to lower interest rates.

Trump claimed at the White House that lowering rates by two percentage points would save the U.S. $600 billion per year, “but we can’t get this guy to do it.”

“We’re going to spend $600 billion a year, $600 billion because of one numbskull that sits here [and says] ‘I don’t see enough reason to cut the rates now,’” Trump said.

Trump added that he was OK with the Fed raising rates if inflation was going up.

“But it’s down,” he said, “and I may have to force something.”