United Airlines said it was cooperating with U.S. and Nigerian investigators to determine what exactly happened on the flight.

WASHINGTON (Reuters) - The U.S. National Transportation Safety Board said on Monday it is investigating a United Airlines flight on Friday from Lagos, Nigeria to Washington D.C., in which a sudden aircraft movement led to injuries of passengers and cabin crew.

Six people were taken to hospital with injuries but have been discharged, United Airlines said.

It is unclear what caused the jolt; United Airlines has said the cause was not severe turbulence, and that it is “working with aviation authorities in the US and Nigeria to understand the cause.”

Six people were injured on a flight from Nigeria to Virginia. The airline also saw a series technical issues in March.

A flight to Washington, D.C., returned to Nigeria after “unexpected aircraft movement” caused injuries, United Airlines said. A statement from United emailed to The Hill on Monday said that one of

The plane headed back to Nigeria after experiencing "unexpected movement" mid-flight on Friday, Jan. 24, according to multiple reports

Nearly 40 people were injured, with six seriously injured, when a Boeing aircraft operated by United Airlines suddenly plunged in mid-air, forcing the fight to make an emergency landing.

Inside United Airlines flight carnage as six hospitalised due to sudden jolt before emergency landing - The cause of the mysterious jolt to the plane is unknown, but US officials are investigating

A United Airlines flight between Nigeria and the US experienced sudden, unexpected movement inflight, injuring 38 people

A United Airlines flight was traveling from Lagos to Washington, D.C. when it experienced "sudden aircraft movement."