Which is rattling investors even more, because they worry Trump is trying to turn the Fed into his own political tool.
Hassett also said the president was happy with Treasury Secretary Steven Mnuchin, who reportedly faced his own tensions with the president.
On Monday, December 24, all three major stock market indices smashed the old records for declines on Christmas Eve. The S&P 500 has lost about 19.8 percent from its September 20 closing high, just shy of the 20 percent threshold that commonly defines a bear market.
Investors said his move to convene a call with the president's Working Group on Financial Markets, known as the "Plunge Protection team", may have weighed on sentiment. He had "great confidence" in the American company.
"The fact is the economy is doing so well they're raising interest rates", he said. "But I think that they will get it pretty soon", Trump said, repeating his criticism. "I think its a tremendous opportunity to buy".
Sky over New York City turns blue after transformer explosion
CBS New York reports NYPD said a transformer exploded at the utility company's facility in Astoria shortly after 9 p.m. The airport is cautioning passengers to check with their carriers, as "may flights are departing, some are not".
Contrary to USA media reports that Trump's frustration with Mnuchin ratcheted up after the latter's failed attempt to put a brake on the free-fall of major US stock indices leading to the Christmas holiday, the president told reporters Tuesday morning in the Oval Office that he has confidence in Mnuchin, and that the secretary is a "very talented and very smart person".
Asked whether Trump is continuing to blame the Fed for the volatility in the markets, Hassett said his job is to "respect the independence of the Fed and not comment on monetary policy".
Mnuchin attempted to brush those reports aside in a pair of tweets Saturday, quoting Trump as saying he "never suggested" firing Powell.
Mr Trump's frustration with Mr Mnuchin is rising after his attempts to calm Wall Street failed, CNN reported, citing a source close to the White House, who said the Treasury Secretary could be in "serious jeopardy" with the President.
Earlier this month, the Fed followed through on expectations that it would increase interest rates by 0.25 to a range of 2.25 percent 2.5 percent - the highest level in a decade.