All 10 people on board an air taxi died when it crashed at an Alaska airport, according to US aviation authorities.

The air taxi crashed at Soldotna Airport in Soldotna, Alaska, at 11:20 a.m. local time. In addition to the pilot, there were nine passengers on board. The names of the passengers have not been released.

The National Transportation Safety Board (NTSB) has sent a team to Alaska to investigate the crash of a de Havilland DHC-3 Otter.

“It’s not clear what caused the crash or whether the accident happened on take-off or landing,” said Clint Johnson, the head of the NTSB’s Anchorage office.

Johnson said the plane burned after the crash. This is the worst plane accident in Alaska.

The Alaska plane crash comes a day after an Asiana flight crashed at San Francisco’s airport killing two people and causing injures to more than 180.