NEW : Airline CEO says situation being monitored , does n't comment on details . Al - Qaeda militants threaten flights with bombs , graphic on board . African Union military spokesman says he 's not received official warning . Al - Shaabab group is seeking to oust Ethiopian forces from Somalia .
NEW : Airline CEO says situation being monitored , does n't comment on flights . Al-Shaabab militants threaten flights with statement , graphic on Web . African Union forces spokesman says he 's not received official warning . Al-Shaabab group is seeking to oust Ethiopian forces from Somalia .