Asian shares fell on Friday after US Federal Reserve held off on raising interest rates, reviving concerns about weakness in both the United States and global economies. The dollar was on the defensive, having fallen more than one percent after the Fed's decision, while U.S. bond yields plunged, erasing their sharp rises in the past couple of days.Nikkei average fell nearly two percent and MSCI's broadest index of Asia-Pacific shares outside Japan dropped 0.2 percent.Commodity prices were relatively well supported with US crude futures last trading at 46.83 dollar per barrel.