- Suicide bomber Ibrahim El Bakraoui blew himself up in the check-in hall of the airport
- His brother Khalid El Bakraoui attacked a metro train at Maalbeek station
- Turkey says one of the brothers was a foreign fighter arrested on Turkish-Syrian border
Belgium's federal prosecutor has confirmed brothers Ibrahim El Bakraoui, 29, and Khalid El Bakraoui, 27, were behind suicide attacks at Brussels Airport and on a metro train station that killed 31 people and injured 300 others.
Ibrahim El Bakraoui blew himself up in the check-in hall of the airport while Khalid El Bakraoui attacked a train at Maelbeek station near European Union headquarters.
The brothers, identified by their fingerprints and security cameras, had a history of crime and had also recently emerged as connected to the Paris attacks.
Ibrahim El Bakraoui was deported last year from Turkey after being detained near the Turkish-Syrian border and Turkish President Tayyip Erdogan said Belgium ignored a warning that he was a militant.
"One of the attackers in Brussels is an individual we detained in Gaziantep in June 2015 and deported. We reported the deportation to the Belgian Embassy in Ankara on July 14, 2015, but he was later set free," Mr Erdogan said.
"Belgium ignored our warning that this person is a foreign fighter."
Mr Erdogan's office confirmed Ibrahim El Bakraoui was deported to the Netherlands.
It said he was later released by Belgian authorities as "no links with terrorism" were found.
In previous cases, officials have said without evidence of crime, such as having fought in Syria, they cannot jail people deported from Turkey.
Third suspect remains on the run
A third man — dressed in a hat and white coat on CCTV footage from the airport — remains on the run after fleeing before detonating his bomb, the federal prosecutor said.
"The third man is on the run; he left his bag with the biggest bomb in it which exploded later because it was so unstable," Frederic van Leeuw said.
He said another man — seen in black on the left of the airport CCTV footage — was still unidentified, but that the one in the middle was confirmed as Ibrahim El Bakraoui.
Earlier, Belgian media had reported the arrest of a suspect but later reported the person detained was questioned and then released.
The group of suspects seem to have been knitted together by time serving in Belgian prisons and fighting in Syria.
Police have also revealed they had found 15 kilograms of TATP high explosives and a mass of bomb-making material during searches in the Schaerbeek district of the Belgian capital.
Mr Van Leeuw said 150 litres of acetone was found as well as detonators, bags filled with nails plus other equipment used to make bombs of the type used in the Brussels attacks.
TATP high explosives have been used extensively by Islamic State jihadists.
'I don't want to end up in a cell next to him'
The prosecutor revealed Ibrahim El Bakraoui left a will saying "I don't know what to do" on a laptop found in a bin.
Ibrahim's will said he was "in a rush ... I don't know what to do, hunted everywhere, no longer safe" and "I don't want to end up in a cell next to him", Mr van Leeuw said.
That appeared to be a reference to Paris attacks suspect Salah Abdeslam, who is reportedly linked to Ibrahim El Bakraoui, and who is in custody in Belgium after being captured last week.
The brothers were already known to authorities for crime not related to terrorism.
Khalid El Bakraoui was sentenced in 2011 to five years in prison for car-jacking, while Ibrahim El Bakraoui was jailed in 2010 for shooting a Kalashnikov assault rifle at police after a robbery.
Released in 2014, he has been sought since mid-2015 for breaching parole conditions.
Meanwhile, Belgians observed a minute of silence on Wednesday in memory of the victims of the bombings, the country's worst-ever terror attacks.
Defiant applause broke out after the symbolic display of solidarity from a large crowd at the central Place de la Bourse, while there was also a large crowd at the headquarters of the European Union.