Short-term interest rate futures traders kept expectations the Federal Reserve will wait to hike rates until late 2011, after the U.S. central bank reaffirmed its commitment to provide stimulus to the economy.

The Fed, already targeting short-term rates at between zero and 0.25 percent, stuck to its commitment to buy $600 billion of Treasury securities through June 2011 to support a recovery it views as still too slow. The purchases come on top of $1.7 trillion of Treasuries and mortgage-backed debt bought largely in 2009.

Fed funds futures traders are now pricing in a 60 percent chance the Fed will hike its short-term rate target by its November 2011 meeting, and just a 30 percent chance of a hike by its September 2011 meeting.

Before Tuesday's meeting, fed funds futures traders were pricing in a 64 percent of a Fed rate hike by the U.S. central bank's November 2011 meeting.

(Reporting by Ann Saphir)