One person has been killed and nine people remain missing, including a child, after a seaplane crashed in Puget Sound in Washington state, the US coast guard said.

The floatplane had been flying on Sunday afternoon from Friday Harbour, a popular tourist destination in the San Juan Islands, to Renton, a southern suburb of Seattle, the agency said.

Four coast guard vessels, a rescue helicopter and an aircraft were involved in the extensive search, along with nearby rescue and law enforcement agencies.

The crash was reported at 3.11pm local time (11.11pm BST). The Coast Guard said one body had been recovered and nine people were still missing as of around 9pm (5am on Monday BST).

The cause of the crash is unknown, authorities said.

The plane went down in Mutiny Bay off Whidbey Island, roughly 30 miles north-west of Seattle and about halfway between Friday Harbour and Renton.

The National Transportation Safety Board said the plane was a de Havilland DHC-3 Otter, a single-engine propeller plane.

Floatplanes are a type of seaplane which have pontoons allowing them to land on water, and they are a common sight around Puget Sound, an inlet of the Pacific Ocean.

There are multiple daily flights between the Seattle area and the San Juan Islands, a scenic archipelago north-west of Seattle that draws tourists from around the world.

These aircraft, which also fly between Seattle and Vancouver, British Columbia, frequently travel over Seattle and land in Lake Washington, not far from the city’s iconic Space Needle.

Renton, where authorities say the flight was headed on Sunday, is at the southern tip of Lake Washington, about 10 miles south-east of Seattle.

In 2019, a mid-air crash in Alaska between two sightseeing planes killed six people.

The Ketchikan-based floatplanes were carrying passengers from the same cruise ship, the Royal Princess, and were returning from tours of Misty Fjords National Monument.