The amphibious vehicle, known as a "duck boat" reportedly capsized when a storm struck Table Rock Lake with strong winds.
An amphibious vehicle carrying tourists on a Missouri lake capsized and sank on Thursday night, killing at least 17 people.
Stone County Sheriff Doug Rader said seven people were hospitalised and several others remain missing after a "Ride the Ducks" boat sank on Table Rock Lake in Branson.
TRT World's Francis Collings reports.
A spokeswoman for the Cox Medical Center Branson said four adults and three children arrived at the hospital shortly after the incident. Two adults are in critical condition and the others were treated for minor injuries, Brandei Clifton said.
Rader said the stormy weather was believed to be the cause of the capsizing. The National Weather Service tweeted that wind gusts of 63 mph were reported around 7:30 pm at Branson Airport.
He also said an off-duty sheriff's deputy working security for the boat company helped rescue people after the accident.
Multiple dive teams from a number of law enforcement agencies were assisting in the rescue and recovery effort. Rader said crews would stay on the scene all night.
"It's going to be a challenging night and tomorrow," the sheriff said.
The local newspaper, the Branson Trilakes News reported that a storm had hit the lake bringing winds in excess of 95 kilometres an hour.
The newspaper quoted Rader as saying that the vehicle had been carrying 31 people when it sank and that there were still five people that were still missing.
Suzanne Smagala with Ripley Entertainment, which owns Ride the Ducks in Branson, said the company was assisting authorities with the rescue effort. Smagala added this was the Branson tour's first accident in more than 40 years of operation.
Branson is about 200 miles (320 kilometres) southeast of Kansas City and is a popular vacation spot for families and other tourists looking for entertainment ranging from theme parks to live music.
Duck boats, known for their ability to travel on land and in water, have been involved in other deadly incidents in the past. They include one in 2015 in Seattle in which five college students were killed when a boat collided with a bus, and one in 1999 that left 13 people dead after the boat sank near Hot Springs, Arkansas.
Safety advocates have sought improvements to the boats since the Arkansas incident. Critics argued that part of the problem is numerous agencies regulate the boats with varying safety requirements.
Duck boats were originally used by the US military in World War II to transport troops and supplies, and later were modified for use as sightseeing vehicles.