The facade of the U.S. Federal Reserve building is reflected on wet marble during the early morning hours in Washington, July 31, 2013. Credit: Reuters/Jonathan Ernst By Sakari Suoninen and Alistair Scrutton FRANKFURT/STOCKHOLM | Thu Sep 26, 2013 1:43pm EDT (Reuters) - The Federal Reserve confused financial markets over scaling back bond buying, two senior officials said on Thursday, with one arguing the central bank should explicitly link tapering to drops in the jobless rate to be more predictable in the future. Fed Board Governor Jeremy Stein said he would have been comfortable with acting at the September 17-18 meeting, and the decision to keep buying bonds at an $85 billion monthly pace had been, for him, a "close call". "But whether we start in September or a bit later is not in itself the key issue - the difference in the overall amount of securities we buy will be modest," he told a monetary policy conference in Frankfurt. "What is much...