U.S. President Donald Trump continued his tirade against the Federal Reserve in a late Wednesday television appearance, laying into the central bank's policy decisions and suggesting it is to blame for Wednesday's sharp market decline.

Saying he's "not happy" with the Fed, Trump told Fox News he could't understand why it was continuing to tighten U.S. monetary policy. The president has previously expressed displeasure with the central bank, and that's led some to fear the institution's independence is at risk.

"The problem I have is with the Fed. The Fed is going wild. I mean, I don't know what their problem is that they are raising interest rates and it's ridiculous," Trump said during a telephone interview with Fox host Shannon Bream. "The problem [causing the market drop] in my opinion is Treasury and the Fed. The Fed is going loco and there's no reason for them to do it. I'm not happy about it."

"Loco" means "crazy" in Spanish.

In recent months, U.S. officials have sought to emphasize that Trump would honor the Fed's historic ability to make decisions independent of political interference. "We as an administration absolutely support the independence of the Fed," Treasury Secretary Steven Mnuchin reportedly said in July.

As recently as Tuesday, Trump had signaled that he understood the importance of maintaining a firewall between the White House and the Fed. Even as he expressed concerns about the Fed's interest rate policy, Trump told reporters at the White House Tuesday that he had not spoken to Fed Chairman Jerome Powell about them.

"I like to stay uninvolved with them. I have not spoken" to Powell all year, Trump said.

Trump's attitude towards the Fed seemed to change Wednesday, however, as fears about rapidly rising rates helped cause the Dow Jones Industrial Average to drop more than 800 points by day's end. The S&P 500 posted its worst day since February and clinched its first five-day losing streak since 2016.

Early on Wednesday afternoon, Trump knocked his central bank as he deplaned from Air Force One in Erie, Pennsylvania for a campaign rally. "I think the Fed is making a mistake. They are so tight. I think the Fed has gone crazy," the president told reporters.

On Thursday, Larry Kudlow, director of the National Economic Council (and a former CNBC contributor) sought to tamp down speculation that Trump might try to exert influence over the Fed. "The president has his own views, he's stated them many times, and there's nothing new here as far as i can tell," Kudlow said in an interview with CNBC. "We know the Fed is independent. The president is not dictating policy to the Fed. He didn't say anything remotely like that. They are independent, and they're going to do what they're going to do."

The Fed has raised interest rates three times this year and is largely expected to hike once more before year-end.

The most recent September rate hike drew criticism from Trump at the time, who said he was "worried about the fact that they seem to like raising interest rates, we can do other things with the money," he said.

—CNBC's Thomas Franck contributed to this report.

This story has been updated to include National Economic Council director Larry Kudlow's comments.