Minutes of the Fed's July 31-August 1 meeting released yesterday had highlighted strong support among policy-makers for more action. But St. Louis Federal Reserve President James Bullard told CNBC television that the economic outlook had brightened since that meeting.

"I do think that the minutes are a bit stale because we have some data since then that has been somewhat stronger," Bullard, who will be a voting member of the policy-setting committee next year, said in an interview.

Bullard also voiced unusually blunt criticism of Europe's response to the sovereign debt crisis in the euro zone, saying he was "pessimistic" on the region's capacity to take robust action, but played down the impact on the United States so far.