Brussels scene: "There was blood everywhere"
Eyewitnesses have described the confusing and horrifying scenes after the two explosions at Zaventem Airport and another at the Maalbeek Metro station in Brussels.
It is feared up to 25 people have been killed in the attacks with a further 35 injured.
Belgian authorities have raised the terror alert level to maximum, diverted all planes, stopped Brussels' Metro service and advised people to stay where they are.
Andrew and Denise Brandt from Arizona, who were in the departure lounge when the blasts hit told The Independent what happened next.
"We were in the departures lounge shopping area when we felt it and heard it. We were standing there, you feel it in your whole body.
"I was like 'that's a bomb, lets go'. People were running, we were just standing there and I said 'lets go!'. So we walked and we saw people running, running, and some people crying, so we knew it was a bomb.
"We found a quiet corner to go reflect in. It was very confusing, they don't manage expectations very well. There was some man who was still sleeping.
We were in Terminal B then we heard later when we were walking up to the Brussels Airlines counter that there was a second explosion. We only heard one"
On the security response she said: "Don't they rehearse these things? Don't they plan for these things?"
"We felt like a wave, you feel it in your whole body, it is like you are in water and someone jumps in the water and you feel that wave. I'm former law enforcement, she [Mrs Brandt] lived in Afghanistan for years.
"We wanted to be away from the crowds. They [the airport staff]have no idea what they are doing. They kept saying 'evacuate'. We were telling airport agents what we felt, that it was an explosion, then they were like 'what?'.
"Then we heard 'evacuate, evacuate'. Then they say 'stay where you are'. Then 'evacuate, evacuate'. But everyone is just standing around. They would not let me take my bag. They said you are not going on the tarmac with your bag. The security people had no idea what they were doing. Where the hell were we supposed to go?"
Zach Mouzoun who arrived on a flight from Geneva 10 minutes before the first blast: "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"
Marc Noel, 63, was going to board a Delta flight to Atlanta, Georgia when the explosions struck:
"People were crying, shouting, children. It was a horrible experience."
He believes his decision to buy a magazine saved his life: "I don't want to think about it, but I would probably have been in that place when the bomb went off."
An airport employee told the BBC he was on the way to a terminal gate when the explosion took place: "At first we thought a billboard falling down. My colleague was looking to see what it is.
"I said; 'run, run'. We were running very fast. My colleague jumped into the [luggage] carousel behind the check-in desk."
Alexandre Brans, 32, said of the attack on the Metro train:
"The Metro was leaving Maelbeek station for Schuman when there was a really loud explosion.
"It was panic everywhere. There were a lot of people in the Metro."
Jordy van Overmier was in the a baggage area after flying in from Bangkok. He told Sky News:
"I got my luggage and then all of a sudden I heard a loud explosion - this boom.
"Initially I thought it was the sound of a suitcase falling down.
"At this point I saw all these policemen running around, shouting and saying 'there was an explosion'.
"There was a lot of panic, with people running around. Policemen, military everywhere. There were ambulances going around. People seemed really shocked ... Everyone seems very shocked and very sad."