Investigators in Brussels have said they are looking for two more people in connection with Tuesday’s bombings in the Belgian capital.
At least 21 people were killed at Maelbeek metro station when a bomber detonated his device on a train.
They are now actively looking for a second bomber who may have been on board.
Police have also issued a wanted notice for the man seen on CCTV images wearing a hat and glasses.
The man, who has not been identified, pushing a luggage trolley at Brussels Airport alongside two other men.
Investigators say they blew themselves up in the terminal, killing at least 10 and injuring dozens.
Police have searched addresses in Anderlecht and in the Schaerbeek district of Brussels.
They have found evidence of bomb-making, including explosives and detonators.
Computer material has also been confiscated.
A number of arrests have been made.