In a statement on Wednesday, Abdullahi Musa, NAMA’s director of public affairs and consumer protection, said the decision to return to Nigeria was made by the pilot based on his assessment of the situation and the perceived safety of landing at the departure airport.

The Nigerian Airspace Management Agency (NAMA) has explained why United Airlines chose to make an air return to Nigeria.

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 taken to hospital, and many more were injured after a United Airlines flight from Lagos heading to Washington D.C. experienced a sudden in-flight movement. The United States has opened a probe into the unexpected movement, as the cause is still unknown.

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.

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