A small plane with nine people on board crashed into a cliffside above Ella Lake in southeast Alaska on Thursday, killing all passengers on board, officials from a charter flight company confirmed. The pilot and eight passengers from a cruise ship were killed in the crash, Holland America Line said. The circumstances surrounding the crash were not immediately clear. The plane was operating a shore excursion and carrying passengers from the cruise ship MS Westerdam, which disembarked from Seattle on June 20. Holland said the plane was owned and operated by Promech Air, a charter company in Ketchikan, Alaska. Promech said the incident happened during a sightseeing tour near Misty Fjords National Monument.