Media playback is unsupported on your device Media caption Footage shot by a passenger shows the aftermath of the turbulence

At least 37 people were injured on board an Air Canada flight after the plane hit severe turbulence and had to make an emergency landing.

The plane, carrying 284 passengers and crew, was travelling from Vancouver to Sydney but was diverted to Hawaii.

Thirty people were taken to hospital in Honolulu on Thursday. Nine had severe injuries, officials said.

Air Canada said the Boeing 777-200 jet "encountered sudden clear air turbulence... two hours past Hawaii".

Passengers reported the cabin being bloodied and dented from passengers hitting the ceiling of the aircraft.

"We all hit the roof and everything fell down," Jess Smith told local TV station KHON. "People went flying."

Alex Macdonald, from Brisbane, told Canadian broadcaster CBC News that those on board were "extremely shocked".

"I saw the people ahead of me hitting the overhead baggage compartments and then just slamming back into their seats," she said.

Image copyright Reuters Image caption Emergency workers assist passengers on Air Canada flight AC33 after it was diverted to Hawaii

Image copyright Sam Rattanasone Image caption Several passengers were photographed wearing neck braces at the airport

Photographs taken inside the aircraft show that oxygen masks were released and service trolleys thrown over during the incident. An Instagram post from one passenger showed he and others wearing neck braces in the airport.

An Australian country band, Hurricane Fall, were also on the flight at the time. The band said in a Facebook post that their vocalist had sustained injuries to his arm and elbow but had been released from hospital.

The plane landed in Hawaii at 06:46 local time (16:46 GMT) on Thursday.

In a statement to the BBC at 23:00 local time (09:00 GMT Friday) Air Canada confirmed that all of those injured had been assessed, treated and released by local hospitals.

The airline said all passengers from the flight had been accommodated in local hotels, with the flight planned to resume later on Friday.

What is clear air turbulence?

CAT - clear air turbulence - occurs in otherwise calm, clear blue skies, without any visual indication such as clouds.

It occurs when masses of air moving at different speeds meet but can't be identified by the naked eye or conventional radar.

Pilots use reports from other aircraft, passed on via air traffic control, to keep track of patches of CAT.

Airlines usually recommend passengers always keep their seatbelts on while seated in case of unexpected turbulence.