Nobody was hurt, but the incident on Tuesday night left passengers stranded in a country difficult for travel because credit cards do not work in Sudan due to U.S. trade sanctions. Banks change dollars only at a very unfavourable exchange rate compared with the dominant black market.

The Cairo-bound Boeing 737-700 took off in Khartoum after a regular stopover following a flight from Nairobi. But it had to return to the Sudanese capital after 20 minutes, three passengers on board flight KQ 320 told Reuters.

"An engine caught fire and the plane suddenly lost much altitude. The pilot made a sharp turn and returned to Khartoum," said Souhair Mohamed Hawala, an Egyptian passenger. "There was panic on board. People were crying or praying."

Other passengers showed what they said were pictures from the damaged wing and engine of the plane.

A Kenyan Airways official said the plane had returned with an unspecified "engine problem" and needed to be repaired in Sudan. "We don't know the cause yet," he said, adding passengers would be booked on the airline's next flight out of Sudan after 24 hours. (Reporting by Ulf Laessing; Editing by Peter Cooney)

• A Permanent Economic Emergency