Christopher Waller, the Fed governor, said downsizing the Fed's $120 billion-a-month asset purchase programme would require "significant further progress" in the economy, while raising interest rates would require "almost dual goals".
"I think restoring 85 per cent of jobs is a major step forward; but it is not enough to support a rise in interest rates," Waller said in an interview.
"We will pay close attention to the different distributive effects of policies," he said. "We see a lot of inequalities in the way the economy recovers."
Inflation is unlikely to worsen and will cool down, but "it will last longer than I thought in May," he said.