A government official said the third suspect had been seen running away from the airport building. Police later found and detonated a third explosive device at the airport.
Security commentators noted that the two men in dark clothes who officials said had died were both wearing gloves on their left hands only. One expert speculated they might have concealed detonators. The man in the hat was not wearing any gloves.
"If you recognize this individual or if you have information on this attack, please contact the investigators," a police wanted notice for the third man read. "Discretion assured."
Belgian police appealed to travelers who had been at the airport and metro station to send in any photographs taken before the attacks in their efforts to identify the bombers.
Explosions at Brussels Airport.