Thirty-one people on an Etihad Airways flight on Thursday were injured after unexpected turbulence hit the plane under an hour before landing. The flight between Abu Dhabi and Jakarta was 45 minutes away from its destination when the "severe and unexpected turbulence" hit.

An update from Etihad said that 31 passengers and crew had been injured as a result of the turbulence. Twenty-two were treated at the airport and released while nine were taken to hospital for treatment.

The return flight from Jakarta to Abu Dhabi on the same day was cancelled, with Etihad offering alternate flights and hotel accommodation to those affected. Luggage racks were reportedly damaged and oxygen masks released during the shaking.

The Airbus A330-200 landed safely in Jakarta where medical teams were waiting to assist them. Indonesia's national transport safety committee inspected the plane on landing.

A number of the passengers were returning from Saudi Arabia after undertaking the Hajj pilgrimage. One passenger told Indonesian news site Okezone that the turbulence hit while passengers were praying: "It happened when I was performing prayer... The plane suddenly began to shake so fast."

Passengers' belongings were said to have been thrown into the aisles during the turbulence. Pictures on social media seemed to show cracks in overhead baggage compartments.

Turbulence can be caused by jet streams and other atmospheric changes, it cannot be detected beforehand. Three different levels of turbulence are registered by flight crews: light, moderate and severe; injuries can usually be prevented by wearing a seat belt.