ANCHORAGE (REUTERS) - Two seaplanes collided in mid-air on Monday (May 13) over southeastern Alaska, killing at least four of those aboard, injuring 10 others and leaving two people missing, US Coast Guard and Federal Aviation Administration (FAA) officials said.

The two aircraft - one with 11 passengers and crew, the other with five people aboard - went down over water about 40km to 48km northeast of Ketchikan, according to Coast Guard Petty Officer Jon-Paul Rios, speaking from Juneau.

The crash site, which the FAA said was at Coon Cove near George Inlet, lies in the vicinity of a popular tourist lodge that runs excursions to the nearby Misty Fjords National Monument, about 480km south of Juneau, Alaska's capital.

One of the aircraft involved was a de Havilland DHC-2 Beaver with five people aboard, and the other was a de Havilland Otter DHC-3 carrying 11 people, FAA spokesman Allen Kenitzer said in an e-mail message, citing information from local authorities.

The Ketchikan-based operator of the larger plane, Taquan Air, said its pilot and nine passengers were rescued and receiving medical attention, but one passenger's fate remained unknown. That group was returning from a flightseeing tour of Misty Fjords when the crash occurred, Taquan said in a statement.

Mr Rios initially reported a total of 10 survivors receiving medical care, with six other people from the two planes listed as unaccounted for. He later said four of the missing had been confirmed as dead.

Neither of the single-engine planes was under air traffic control when they collided, and the circumstances of the crash were not immediately known, Mr Kenitzer said.