At least 26 people have been killed and many seriously injured in terrorist attacks at Brussels international airport and a city metro station.
Another explosion struck Maelbeek metro station an hour later. Officials say 15 people were killed and 55 injured, 10 seriously.
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”.