UPDATE: BELGIAN PROSECUTORS CONFIRM EXPLOSIONS WERE RESULT OF SUICIDE ATTACK
Earlier this morning, two explosions were heard at Brussels airport.
The airport has been closed and flights cancelled, while rail routes to Zaventem airport have been diverted.
Sky News Middle East correspondent Alex Rossi, who was at the airport at the time, said: "The word is definitely two explosions. The thinking here by everybody is that it is some kind of terrorist attack although that hasn't been verified by anyone here at the airport.
"No word too of casualties. Don't know how the explosion took place, the method if you like. But it certainly seems Brussels airport has been targeted in a terrorist attack.
"We are all being moved out of the airport now towards the emergency exit. There is a great deal of confusion here. Certainly there are a number of very upset, as you might imagine, very frightened people."
He added: "There are fears that there might be other attackers."
There have been reports of up to 23 people killed, and 35 others severely injured in the departure halls.
There has since been a third explosion at Maalbeek Metro station, in what has been claimed to have been a ‘suicide attack’.
Several people were injured in the blast.
Brussels is now in lockdown, with metro stations and the city’s museums closed down.
Prime Minister David Cameron has since tweeted his concern, writing: “I am shocked and concerned by the events in Brussels. We will do everything we can to help.”
He has added that he will to chair a meeting of the UK government’s emergency committee, Cobra, in the wake of the Brussels attacks.
Eurostar trains to and from Brussels have now been cancelled.
We will bring you more on this story as it develops.