By Lucia Mutikani WASHINGTON (Reuters) – U.S. employers hired the fewest workers in nearly three years in December, but the setback was likely to be temporary amid signs that unusually cold weather may have had an impact. The surprisingly weak job growth figures reported by the Labor Department on Friday, however, could cause some discomfort at the Federal Reserve, which last month announced plans to scale back its massive monetary stimulus program. Nonfarm payrolls rose only 74,000 in December, the smallest increase since January 2011 and well short of the 200,000 jobs or so that most economists had expected. Michael Feroli, an economist with JPMorgan Chase in New York, called the report "an ugly mix" but said: "We'd guess the underlying trend in job growth hasn't materially shifted." U.S. stock prices were little changed, but yields on benchmark Treasury debt fell by the most since October.