The planes collided in the vicinity of George Inlet, near Ketchikan (Google Maps)

Five people were killed, 10 others were injured and one person was unaccounted for after two floatplanes collided in midair Monday near the southeast Alaska town of Ketchikan, injuring 10 other people, one critically, authorities said.

File photo of Ketchikan by VCG

The planes collided under unknown circumstances, Federal Aviation Administration spokesman Allen Kenitzer said in an email to The Associated Press. Floatplanes have pontoons mounted under the fuselage so they can land on water.

Eleven people were inside the single-engine de Havilland Otter DHC-3 when it went down. Ten were taken to a Ketchikan hospital. Five people were aboard the other plane, a de Havilland DHC-2 Beaver.

A passenger on the Royal Princess cruise ship told the AP that 14 people on the downed floatplanes were cruise passengers.

Cindy Cicchetti said the ship captain announced that two planes were in an accident Monday. She said the ship is not leaving as scheduled and there weren't any details as to how the accident will affect the rest of the trip.

The FAA and the National Transportation Safety Board are investigating.

Weather conditions in the area on Monday included high overcast skies with 9 mph (14 kph) southeast winds.