It could take a few years for the U.S. economy to recover from the damage caused by the coronavirus pandemic, and it is not yet the time to think about raising interest rates, New York Fed President John Williams said on Thursday.

"This is not the time to think about liftoff or normalization," Williams said during an interview with Yahoo Finance.

The virus has created an "enormous amount of uncertainty" and even if the U.S. economy begins to recover in the second half of 2020, it may take some time for the economy to come out of a "very deep hole."

"We have a long ways to go to get back to full strength," Williams said.

The rebound is starting to stall in states where the number of coronavirus cases is rising, a trend that is causing people to cut down on trips to restaurants and other activities, Williams said.

Fiscal stimulus delivered to households and businesses in the form of cash transfers or grants have been effective at supporting workers and small businesses, Williams said.

Williams reiterated the Fed's goal of hitting its 2% inflation target, but said it could be challenging at a time when rates are low.

"The goal here is we want inflation to be anchored at 2%," Williams said.

"That's been harder to do than to say and I would argue that much of that is because of this issue of the lower bound on interest rates and the limited ability in a global situation of very low interest rates to really provide accommodation and stimulus as needed."

Asked about the potential use of yield curve control to target rates at specific maturities, Williams said it would best be used in situations where forward guidance wasn't being as effective as Fed officials would like. 

Meanwhile, Chicago Federal Reserve Bank President Charles Evans said there's little reason for the Federal Reserve to raise interest rates until inflation rises above the Fed's 2% target, noting that he expects low inflation to be a problem for the next few years.

Evans forecast U.S. unemployment to fall only to 6.5% by the end of next year, well above the 4.5% most Fed policymakers see as consistent with full employment.

Even if unemployment falls below 4%, experience has shown that inflation won't respond by surging, Evans said.

"I am hard pressed to think of reasons why we would need to move away from accommodative monetary policy unless inflation was well above 2% for an extended period of time, and the economy was just very different from what we are seeing right now," he said in a virtual event held by the Global Interdependence Center. "That doesn’t seem to be very likely."

The Fed has slashed interest rates to near zero and bought trillions of dollars of bonds to shore up financial and credit markets during the COVID-19 crisis. Monetary policy, he said, needs to be positioned to battle downside risks to the economy, such as those posed by a resurgence in infections across the country. Central to that, he said, is getting across the message that the Fed will stay accommodative even as the unemployment rate drops, as long as inflation doesn't careen out of control.

"I think it's very important that we get inflation up to 2%; I'm looking for that to be a real problem over the next few years," he said.