Somali - Investigators believe a bomb likely caused the explosion aboard a plane that was forced to return to the Somali capital of Mogadishu for an emergency landing on Tuesday, two U.S. government sources said on Wednesday.

The sources also told Reuters on condition of anonymity that hard forensic evidence was lacking and no group is known to have claimed responsibility for the blast.

One person died on Tuesday when the Daallo Airlines Airbus A321 carrying 74 passengers was forced to return after a blast tore a hole in the fuselage.