The Federal Reserve may be contributing to the next asset price bubble through its aggressive purchase of bonds to spur U.S. growth, while its near-zero interest rates could trigger future inflation, a senior Fed official said on Thursday.

Kansas City Federal Reserve President Esther George, in remarks that will clearly stamp her as a hawk on the U.S. central bank's policy-setting committee, went out of her way to make clear that she is not comfortable with recent Fed action.