Divers have found four more bodies in a Missouri lake where a duck boat packed with tourists capsized and sank in high winds, bringing the death toll to 17.
Investigators blamed stormy weather for the accident on Thursday evening on Table Rock Lake in the tourist town of Branson, with winds reaching speeds of more than 100km/h at the time, according to the US National Weather Service.
Fourteen people survived, including seven who were injured when the boat went down, state police said.
Duck boats, named for their ability to travel on land and in water, have been involved in other deadly incidents in the past.
Five college students were killed in 2015 in Seattle when a duck boat collided with a bus, while 13 people died in 1999 when a boat sank near Hot Springs, Arkansas.
Andrew Duffy, an attorney whose Philadelphia law firm handled litigation related to two fatal duck boat accidents there, said: “Duck boats are death traps.
“They’re not fit for water or land because they are half car and half boat.”
Safety advocates have sought improvements and complained that too many agencies regulate the boats with varying safety requirements.
The boats were originally designed for the military, specifically to transport troops and supplies in the second World War. They were later modified for use as sightseeing vehicles.
Passengers on a nearby boat described the chaos as the winds picked up and the water turned rough.
"Debris was flying everywhere," Allison Lester said in an interview on Friday with ABC's Good Morning America.
A severe thunderstorm warning had been issued for Branson at 6.32pm on Thursday, about 40 minutes before the boat tipped over.
Ms Lester's boyfriend, Trent Behr, said they saw a woman in the water and helped to pull her into the boat. He said he was about to start CPR when emergency services arrived and took over.
The driver of the Ride The Ducks boat died, but the captain survived, Stone County Sheriff Doug Rader said.
Divers located the vessel, which came to rest on its wheels on the lake bed, and authorities planned to recover it later.
The boat sank in 40ft of water and then rolled on its wheels into an area twice as deep. Investigators had no information about whether passengers were wearing life jackets or whether they were stowed on board, the sheriff said.
The names of the dead were not immediately released.
A spokeswoman for Cox Medical Center Branson said four adults and three children arrived at the hospital shortly after the accident. Two adults were in critical condition, and the others were treated for minor injuries, Brandei Clifton said.
Suzanne Smagala with Ripley Entertainment, which owns Ride the Ducks in Branson, said the company was assisting authorities. She said this was the ride's only accident in more than 40 years of operation.
US president Donald Trump tweeted his condolences, extending his sympathies to the families and friends of those involved. – AP