Belgian media is reporting that at least two people suspected of being involved in the deadly attacks in Brussels may be at large.
On Tuesday morning, there were two explosions at Brussels Airport. Shortly after, there was a third explosion at Maalbeek Metro Station.
Terror group Isis claimed responsibility for the attacks, which killed at least 31 people and wounded up to 270 others.
Two suicide bombers at the airport have been named as Ibrahim, also known as Brahim, el-Bakraoui and Najim Laachraoui.
Brahim's brother, Khalid, has been named as the attacker who blew himself up Maalbeek Metro station.
Here is what we know so far:
- The second suspect believed to be on the run, who has not been identified, was filmed on CCTV cameras at Maalbeek Metro station carrying a large bag alongside Khalid el-Bakraoui
- Of the three men captured on CCTV at the airport, two are known to be dead: Brahim el-Bakraoui (centre of image) and Najim Laachraoui (right of image)
- It was initially thought that Laachraoui was on the run. There were also reports that he had been detained on Wednesday morning, but the person arrested was not him
- Police are continuing to hunt for a third unidentified airport attacker (left of image)
- Salah Abdeslam's lawyer has said his client did not know about the Brussels attacks
- Belgium's interior minister Jan Jambon and justice minister Koen Geens have offered to resign over revelations they were warned about one of the attackers. Prime Minister Charles Michel has rejected the offers
- Passenger flights at Brussels Airport are suspended until the end of Sunday
- The number of Britons injured has risen to six, according to Downing Street. Four have been discharged from hospital
- Concerns remain for the whereabouts of 53-year-old David Dixon
What happened on Wednesday?
- Belgian media has named two suicide bombers involved in the attacks in Brussels as brothers Khalid and Ibrahim, also known as Brahim, el-Bakraoui.
- Brahim el-Bakraoui, from Belgium, was one of the airport suicide bombers, according to federal prosecutor Frederic Van Leeuw. Brahim left a will on his computer found in a bin in the neighbourhood of Schaerbeek
- Khalid el-Bakraoui, 27, from Belgium, blew himself up on a metro carriage at Maalbeek station
- Belgian authorities have said several other people who may be linked to the attacks are still on the loose
- The first victim of the attacks has been named as Adelma Tapia Ruiz, a 37-year-old from Peru who was killed at the airport
- The Moroccan Embassy in Belgium confirmed to The Independent that a Moroccan woman died in the attacks
- Saint-Louis University in Brussels has said student Leopold Hecht died at the metro station, according to Sky News
- The Federation Wallonie-Bruxelles, a government organisation, has said one of its employees, Olivier Delespesse, was killed on the metro
- 15kg of TATP explosives were found in the house which the suspects left from for the airport, says prosecutor
- British man David Dixon is reported missing following the attacks - he is thought to have been on the metro at the time of the explosion
- Four Britons are among those injured, says Downing Street
- Three days of national mourning has begun - a minute's silence was held for the victims at midday local time
- Brussels Airport is closed. It is to remain closed on Thursday
- Brussels’ Metro Network is partially open
- French Prime Minister Manuel Valls urged the EU parliament to authorise a passenger name record (PNR) covering Europe. He later said EU nations would "have to invest massively in their security system"
- Neil Basu, of the UK Counter Terrorism Policing Network, said police and intelligence agencies were working hard to foil a similar attack in the UK
- Australian Prime Minister Malcolm Turnbull blamed "weakness in European security"
- Queen Elizabeth said she was "deeply shocked and saddened by the loss of life and injuries after the terrorist attack in Brussels"
- The football match between Belgium and Portugal, scheduled for next Tuesday, has been called off
What happened on Tuesday?
Shortly after 8am local time, two explosions were heard minutes apart in the departure hall of the airport.
- Belga news agency reported that shots were fired and shouts in Arabic could be heard before the explosions
- People could be seen fleeing the airport as smoke rose from the terminal building
- An eyewitness said: "It was atrocious. The ceilings collapsed. There was blood everywhere, injured people, bags everywhere"
- Officials have urged people to stay away from the airport
- Brussels Airport has also told people to avoid the area, and it has cancelled all flights. It is expected to stay closed until about 6am on Wednesday
- At least one Kalashnikov assault rifle was found in the departure lounge, according to a European security official
- Florence Muls, the airport communications manager, has defended the security at the site, adding that the airport does not have the ability to impose controls at the terminal entry
Maalbeek Metro station
About an hour after the airport blasts, there was an explosion at Maalbeek Metro station, which is close to a number of EU institutions
- A photo from VRT showed that a train carriage was struck by the blast
- The entire Metro system in Brussels has been shut down
- Eurostar has suspended its services to Brussels-Midi station
- The public transport system in Brussels has been closed
- The European Commission has told people to stay at home or inside buildings. All EU institutions are on alert level orange
- The Facebook "safety check" system has been activated
- Phone networks in Belgium crash as people attempt to contact their friends and loved ones
- Belgium's national football team cancelled their morning training session following the explosions
- Charles Michel, the Prime Minister of Belgium, has condemned the "hateful attacks"
- David Cameron, the UK Prime Minister, will be holding a COBRA meeting following the attacks in Brussels
- Dutch Prime Minister Mark Rutte said Belgium had again been "hit by cowardly and murderous attacks"
- French President Francois Hollande said: "Terrorists struck Brussels, but it was Europe that was targeted"
- Heiko Maas, Germany's justice minister, said it was "a black day for Europe"
- People around the world have been showing their solidarity with Belgium with images of Tintin, the character created by Belgian cartoonist Herge, circulating on Twitter
- Downing Street in London raised the Belgian flag and the Eiffel Tower in Paris is to be lit in the colours of the Belgian flag
- Isis have threatened to bring more "dark days" to Europe
- Belgian federal police issued a wanted notice for one of the suspects captured on CCTV before the Brussels Airport bombing
- Police have detained one man in a raid which uncovered an Isis flag, chemical products and a nail bomb
This article will be updated as more information becomes available.
Additional reporting by agencies
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