Cruise passengers killed as sightseeing planes collide in mid-air in Alaska

At least four people have been killed and another two are missing after two sightseeing seaplanes collided in mid-air in southeast Alaska.

Ten other passengers have been taken to hospital following the incident on Monday near the town of Ketchikan.

Eleven people were inside a single-engine de Havilland Otter DHC-3 operated by Taquan Air when it went down as it returned from Misty Fjords National Monument.

Three people who died were among the five on board the second plane, a single-engine de Havilland DHC-2 Beaver, according to the US coastguard.

It is unclear which plane carried the fourth victim.

All passengers were from the cruise ship Royal Princess.

Taquan Air, operator of the Otter, has suspended operations while federal authorities investigate the deadly crash.