Terrorist Bomb Blasts Rock Brussels, At Least 26 Dead, Dozens More Injured.
Many people have been killed or seriously injured in terrorist attacks at Brussels international airport and a city metro station, Belgium's PM says.
Two blasts hit Zaventem airport at about 07:00 GMT, and another struck Maelbeek metro station an hour later.
The government has not confirmed casualty numbers. Brussels transport officials say 15 died at Maelbeek and media report 11 dead at the airport.
Belgium has now raised its terror threat to its highest level.
The attacks come four days after Salah Abdeslam, the main fugitive in the Paris attacks, was seized in Brussels.
Prime Minister Charles Michel called the latest attacks "blind, violent and cowardly", adding: "This is a day of tragedy, a black day... I would like to call on everyone to show calmness and solidarity".
European Council president Donald Tusk said: "These attacks mark another low by the terrorists in the service of hatred and violence."
The airport and whole transport system in Brussels are closed.
'Blood everywhere'
Two blasts tore through the departures area of Zaventem airport shortly after 08:00 local time (07:00 GMT).
The Belgian prosecutor said "probably a suicide bomber" was involved.
Belgian media quoted the health minister as saying 11 people had died and 81 were injured.
The Belga news agency reports that shots were fired and shouts in Arabic were heard before the two explosions.
Zach Mouzoun, arriving on a flight from Geneva, told France's BFM television: "It was atrocious. The ceilings collapsed. There was blood everywhere, injured people, bags everywhere. We were walking in the debris. It was a war scene."
All flights have been diverted. Eurostar has cancelled all trains to and from Brussels. The Thalys France-Benelux train operator says the entire network is closed.
Security has been stepped up at Gatwick and Heathrow airports and the UK Foreign Office has advised British nationals to avoid crowded areas in Belgium. UK PM David Cameron is chairing a meeting of the Cobra response committee on Tuesday.
France has stepped up security. President Francois Hollande has held a cabinet meeting to discuss the Belgian explosions.
He said: "The terrorists have struck Belgium but it is Europe that was targeted. And it is the whole world that is concerned with this."
There is also extra security at Dutch airports.