St. Louis Federal Reserve bank President James Bullard said on Thursday that he is hopeful the worst of the economic crisis caused by the coronavirus pandemic may have passed in April, but the U.S. economy is not yet in the clear.

"I definitely don't think we're out of the woods," Bullard said during a virtual conference. "We're still at a high, high risk level here. Any crisis, I think you have to keep in mind that many things can happen - many twists and turns can occur."

Bullard said he expects the U.S. economy to rebound more quickly than it did during the 2007 to 2009 financial crisis, but that the pace of the recovery will depend on the coronavirus.

The shutdowns rolled out this year were appropriate to slow the spread of the virus, but they are not sustainable in the long term because many businesses cannot survive several months without revenue, Bullard said.

"If you get massive business failures, you'll face depression risk or financial crisis risk or both," Bullard said. "And we want to stay out of those situations," he said, adding that his base case is for that dire scenario to be avoided.