What we know so far
• Twin explosions at Brussels airport, one a suicide bomber
• At least 11 dead and 81 wounded
• Shots and Arabic heard beforehand, witnesses say
• Bombs went off at 8am in departure hall
• More than 200 flights to Brussels diverted or cancelled, according to flight tracking service Flightradar24
• Trains to airport suspended
• Metro train hit at Maelbeek station near European Parliament buildings
• At least 15 dead and 55 wounded says public transport operator STIB
• Metro system shut down
• Attacks come four days after arrest of Paris terror attacks suspect Salah Abdelslam in Brussels
• Belgium's security raised to highest level, 4
• No one has claimed responsibility for the attacks
10pm: Police are ordering people off the streets of Brussels.
9.59pm: The Eurostar has been suspended and extra security has been added at Paris airports.
9.57pm: British Prime Minister David Cameron said on Twitter: "I am shocked and concerned by the events in Brussels. We will do everything we can to help."
9.56pm: The New Zealand Ambassador to the European Union, Sweden and NATO, David Taylor, has just tweeted: "Thanks all accounted for. But situation still unfolding..."
9.54pm: NBC News is reporting there have now been four explosions at different metro stations as well as two at the airport.
9.50pm: Sixty New Zealanders are registered on SafeTravel as being in Belgium.
"The New Zealand Embassy in Brussels is currently seeking information on the nationalities of victims and casualties from two explosions at the airport in Brussels, and is liaising with local authorities," a Ministry of Foreign Affairs spokesman said.
There is currently no confirmed information on nationalities of victims, the spokesman said.
• If you have concerns about a New Zealand family member in Belgium, try and make direct contact in the first instance.
• If you have ongoing concerns, contact the Ministry of Foreign Affairs and Trade - Tel:Â 04 439 8000 (if calling from within New Zealand) or Tel: +64 4 439 8000 (if calling from outside New Zealand).
9.45pm: Local Belgian media are reporting police have found three unexploded devices in the airport departure hall.
9.42pm: Brussels central is being evacuated and all metro stations are closed.
9.40pm: All rail services shut down in Brussels and explosion at metro station near EU buildings confirmed, according to Sky News.
9.30pm: Smoke can be seen pouring from near the Brussels metro at Maalbeek.
9.28pm: BBC is reporting a third explosion at a metro station in central Brussels close to European Union institutions.
9.20pm: There are unconfirmed reports that there are 11 dead and before the two explosions, there were shots fired and shouts in Arabic.
Images from people at the scene show injured people with torn, bloodied clothes and covered in dust.
People evacuating have been told by officials to "leave their bags" sop police could check for more explosives but some ignored the instructions, the Daily Mail is reporting.
Evacuated passengers are being ferried onto buses and are being driven to a crisis centre away from the airport. Women and children are being moved first.
9.15pm: Belga's news agency reports shots were fired before the explosions. A man was heard shouting in Arabic before the blasts, the agency said.
The explosions happened just before 8am local time.
Roofing tiles can be seen strewn across the floor of the departure lounge.
Two explosions have rocked Brussels airport, injuring several people and forcing authorities to evacuate the terminal and cancel flights.
The Belgian fire service have told local media that there are several dead and wounded at the airport, according to the BBC.
Brussels Airport have tweeted a message, confirming the explosions.
"There have been 2 explosions at the airport. Building is being evacuated. Don't come to the airport area."
The airport then tweeted: "Don't come to the airport - airport is being evacuated. Avoid the airport area. Flights have been cancelled."
Footage shows people fleeing and screaming shortly after the explosions at the departure terminal at Brussels Zaventem Airport this morning (this evening NZT). Smoke can be seen rising from blown-out windows.
Flights have been cancelled, passengers are being evacuated, and transport links to the airport have been stopped.
Several people were understood to have been injured in the blasts, which happened near the American Airlines check-in area.
Sky News reporter Alex Rossi was at a duty when he heard "two very, very loud explosions".
"I could feel the building move. There was also dust and smoke as well," he told Sky News.
"I went towards where the explosion came from and there were people coming out looking very dazed and shocked.
"The thinking here is that it is some kind of terrorist attack - that hasn't been verified by any of the authorities here at the airport."
A Sky News reporter at the scene said people were being moved out of the airport through emergency exits by officials.
"There is a great deal of confusion here. There are certainly as you can imagine a number of frightened people ... the people I am with here certainly believe that there is a terrorist attack but we can't confirm it's an attack."
He said there were fears there would be further attacks.
Top Paris attacks suspect Salah Abdeslam, Europe's most wanted man, was wounded and captured in a raid by armed police in Brussels on Saturday after four months on the run.
Abdeslam was plotting fresh atrocities in Brussels with a new extremist network when he was captured, the Belgian Foreign Minister said on Monday.
"He was ready to restart something in Brussels," Didier Reynders said. "We found a lot of weapons, heavy weapons, in the first investigations and we have found a new network around him in Brussels."
Abdeslam, 26, is in a Belgian prison, charged with terrorism offences and murder.
He was thought to have fled to Brussels the day after the gun and bombing rampage on Paris nightspots after refusing to blow himself up.
The arrest came hours after prosecutors revealed that Abdeslam's fingerprints were found in an apartment in another part of Brussels following a raid earlier this week in which a suspected Isis militant was killed.