We mentioned earlier that aircraft have been turning back rather than landing at Khartoum airport, after reports that two people were killed when a shell hit a passenger plane.
Since then, two airlines have issued statements.
State-owned Saudi Arabian Airlines said that one of its Airbus A330 jets "had an accident" at Khartoum before its scheduled departure for Riyadh at 07:30 GMT.
The airline added that it was working with the Saudi embassy in Sudan to establish what happened and that flights to and from Khartoum had been suspended until further notice.
Egyptian national carrier EgyptAir said it was suspending flights to and from Khartoum for 72 hours.
