A fire that may have been arson damaged three floors of a London hotel near Buckingham Palace, killing two people and forcing the evacuation of more than 300 guests and employees, authorities said. The fire began about 3 1/2 hours after guests were roused by what proved to be a false alarm at the six-story Rubens Hotel, which overlooks the Royal Mews of Buckingham Palace. Police identified the dead as a 58-year-old Australian woman and a Sudanese man of 45. Scotland Yard said the fire may have been arson, but no arrests were announced immediately. Officials said there was no indication of a link between the false alarm and the fire.