Federal Reserve Vice Chairman for Supervision Randal Quarles brushed off the suggestion that President Trump has hurt with the Fed's independence, despite Trump calling the central bank “crazy” for raising interest rates.

“There has not been any effort to undermine that independence,” Quarles said Thursday during public remarks at the Economic Club of New York. “We’ve stayed pretty focused on the facts about the economy. It is not unprecedented for a president to have views on Federal Reserve policy.”

Quarles, a Trump appointee, said he remained optimistic about economic growth, but wouldn’t fully commit to the Trump administration’s assessment that the economy can consistently grow at a rate above 3 percent annually.

“The U.S. has gone through significant periods in its history where it has grown at 3 percent, so I do think that is a potentially sustainable rate,” said Quarles. The Fed recently raised its growth projections for the year to slightly above 3 percent, a victory for Trump.

Quarles also downplayed concerns that there may not be enough workers to fill the over 7 million job openings estimated by the Labor Department. More people returning to work and increased productivity could raise the potential of the economy, he argued.

“I am hopeful that potential growth, and particularly productivity, could accelerate from its relatively anemic pace of late, sustaining growth without overheating the economy. The more the economy's potential growth increases, the more gradual we can be in our removal of monetary policy accommodation,” Quarles said in prepared remarks. He added that he thought labor force participation could move up, despite an overall aging population in the U.S., because of the current economic boom -- an argument echoed by the Trump administration.

The number of workers that the economy can continue to draw in is a source of debate among experts. The Trump administration’s hawkish immigration policy means that the economy must rely more on domestic workers to fill openings, but it’s unclear how many more people are looking for work, a question the Fed must wrestle with as it steers the economy through relatively uncharted territory. Businesses across the country have told the Fed they can’t find enough workers to invest in new opportunities, though the stable labor force participation rate indicates that the current economic boom could be attracting more people to work.

Quarles argued that the Fed should continue a course of gradual interest rate increases, slowly putting brakes on inflation, the potential rise in cost of goods. But he left open the possibility that the Fed could raise rates more slowly, with a higher overall goal set over a longer period of time if the central bank sees a higher ceiling for the economy.

“I do think we’ll be able to follow a gradually increasing path over a period of time,” said Quarles.

Quarles, who also plays a key role in the Fed’s financial regulation policy, also cautioned against requiring banks to raise more capital to protect against a potential downturn, which some Democrats favor.

“We have extremely high capital levels in this country, our banks are very highly capitalized, that’s one of the strengths of our system,” said Quarles. “We wouldn’t really have the headroom,” to increase it without affecting economic growth, he argued.

“This still remains quite a strong economy,” the Fed vice-chairman concluded.