Belgium is observing three days of mourning after three bomb blasts in Brussels killed at least 34 people and wounded more than 200.
Twin explosions at Zaventem airport and another at a metro station on March 22 were claimed by the Islamic State extremist group.
On March 23, Belgian media named two suicide bombers who attacked the airport as the brothers Khalid and Brahim el-Bakraoui. The RTBF broadcaster said the pair was known to police.
A third man pictured with them at the airport is still being sought. One report identified him as Najim Laachraoui, a man already sought by police.
One of the brothers reportedly used a false name to rent the flat in the Forest area of Brussels where police killed a gunman in a shoot-out last week.
During that operation, police found fingerprints of Salah Abdeslam, the chief surviving suspect in the Paris attacks, who has since been arrested.
Meanwhile, hundreds of people gathered in a historic city square overnight, lighting candles and placing flowers in a vigil for the victims.
A minute of silence will be held at midday on March 23.
