Four people are missing after two boats crashed and sunk on the Colorado River, ejecting more than a dozen people who were on board.
A recreational boat carrying 10 people and another vessel with six people on board collided head-on on a well-travelled stretch of the river that marks the border between California and Arizona, the Mohave County Sheriff's Office said.
Both boats sank, and passing boaters pulled crash victims from the water.
Nine people were injured, with two in critical condition, authorities said.
The crash occurred between two popular marinas and near Moabi Regional Park, a well-travelled recreation area crowded with people enjoying the Labour Day weekend.