Several people have been injured and one dead after two explosions rocked Brussels Airport.
Witnesses said they 'felt the shockwaves' of the blasts which are believed to have centred on the American Airlines check-in desk at 8am (7am GMT). Pictures show the terminal windows blown out from the force of the explosion and smoke rising high into the sky.
Video also shows terrified passengers running for their lives out of the terminal.
Sky News Middle East correspondent Alex Rossi, who was at the airport en route for Tel Aviv, told the channel: 'I could feel the buildings move.'
The incident came as the Belgian capital was on a state of high alert following the arrest of Paris terror attack suspect Salah Abdeslam in the city last week.
Belgium's Interior Minister, Jan Jambon, said the country was on high alert for a possible revenge attack following the capture of 26-year-old Salah Abdeslam in a flat in Brussels on Friday.
'We know that stopping one cell can ... push others into action. We are aware of it in this case,' he told public radio.
France is seeking his extradition so he can stand trial for his alleged role in the November 13 rampage of gunfire and suicide bombings that killed 130 people in Paris.
Belgium is under great tension, with its federal prosecutor Frederic Van Leeuw saying yesterday that last year the country worked on 315 new anti-terror cases and nearly 60 so far this year.