US stocks fell on Wednesday with the S& P 500 posting its biggest decline in three weeks, after minutes from the latest US Federal Reserve meeting showed some officials were open to tapering large-scale asset purchases as early as at the June meeting.

Trading was volatile - the Dow and the S& P indexes both rose more than 1 per cent during the morning, but fell more than 1 per cent in the afternoon.

The minutes followed comments from Chairman Ben Bernanke, who said the Fed could decide to scale back the pace of bond purchases at one of the " next few meetings" if the economic recovery looked set to maintain forward momentum.

The comments were a blow to a market that had accelerated after Bernanke said the central bank needed to see further signs of traction in the economy before it tapered stimulus.