Two people have died when a speedboat flipped over in waters off Cornwall.
Four others were seriously injured in the crash in the Camel Estuary off Padstow in North Cornwall.
The Maritime and Coastguard Agency confirmed the injured people had been flown to Derrfiord Hospital in Plymouth for treatment.
John Oliver from South Western Ambulance Service said children and adults had suffered leg injuries of various degrees of severity.
It is not yet known if they were in the speedboat or in the water at the time of the collision.
Ambulance staff were initially called to reports the boat had come into contact with a number of kayakers.
Jo Rawlings, from the Maritime and Coastguard agency, said: "Falmouth coastguard was contacted at 15:50 BST with reports that six people had been thrown from a speedboat near Padstow harbour.
"It was also reported the boat was out of control for some time and had struck some other boats in the water."
Matt Pavitt, the Coastguard sector manager for North Cornwall, said the four flown to hospital were "badly shaken up" by the incident.
The Rock and Padstow lifeboats, coastguard rescue teams, and search and rescue helicopters were all called to help the group.
Police are also at the harbour, an area of which has been cordoned off.