Police issued a wanted notice for a young man pictured pushing a laden luggage trolley at the airport where two others were suspected of blowing themselves up, Reuters reports.
The coordinated assault triggered security alerts across Europe and drew global expressions of support, four days after Brussels police had captured the prime surviving suspect in Islamic State’s attacks on Paris last November.
Belgian security officials made little comment but U.S. officials said that while the attacks may have been triggered by the arrest of Salah Abdeslam, the level of organization involved suggested that they had previously been in preparation.
A witness said he heard shouts in Arabic and shots shortly before two blasts struck a packed airport departure lounge at Zaventem airport.
Belgian media published a security camera picture of three young men pushing laden luggage trolleys. Police later issued the same photograph, showing only one of the three, saying the unidentified man in a hat and wearing glasses was a suspect.
“If you recognize this individual or if you have information on this attack, please contact the investigators,” the notice read. “Discretion assured.”
Police operations were under way at several points in the city but a lockdown imposed immediately after the attacks was eased and commuters and students headed home as public transport partially reopened.
Islamic State issued a statement claiming responsibility: “We promise the crusader alliance against the Islamic State that they will have black days in return for their aggression against the Islamic State,” the jihadist group said.
Belgium, home to the European Union and the headquarters of the NATO military alliance, has sent warplanes to take part in operations against Islamic State in the Middle East.
Austrian Horst Pilger, who was awaiting a flight with his family when the attackers struck, said his children had thought fireworks were going off, but he instantly knew an assault was underway.
“My wife and I both thought ‘bomb’. We looked into each other’s eyes,” he told Reuters. “Five or 10 seconds later there was a major, major, major blast in close vicinity. It was massive.”
Pilger, who works at the European Commission, said the whole ceiling collapsed and smoke flooded the building.
Security services found and destroyed a third bomb after two blasts at the airport killed at least 10 people and injured around 100, the provincial governor of Brabant Flanders said. Belgian media gave death tolls as high as 14 at the airport.
The metro station blast killed a further 20 people and injured roughly 130, according to a provisional toll from the national crisis response center.