Secretary of State John Kerry has paid tearful thanks for the outpouring of good wishes for his wife Teresa Heinz Kerry and says her condition is improving.

Kerry, looking weary, was speaking at the opening of U.S.-China talks at the State Department Wednesday.

Kerry returned to Washington from his wife's hospital bedside in Boston. Kerry said: "Teresa is doing better, under evaluation and we hope improving."

Kerry thanked everybody for "the remarkable outpouring of good wishes. It's really been very special."

He added that when Mrs. Kerry is able, she will "tell everyone herself." The 74-year-old Kerry was hospitalized after becoming ill Sunday on the Massachusetts island of Nantucket, where the couple owns a home.