Brussels attacks timeline: How bombings unfolded at airport and Metro station

Two explosions near check-in desks at Brussels Airport were followed around an hour later by a blast at Maalbeek station

Emergency rescue workers stretcher an unidentified person at the site of an explosion at a metro station in Brussels (AP)

At least 30 people have died in twin bombings at and many wounded after a suspected suicide bombing and explosions at Brussels Airport and a Metro station in the Belgian capital.

Here is how the attacks unfolded (all times local):

8am: Gunfire heard in the departures terminal of Brussels Airport. One blast heard by check-in desks, passengers start running. A moment later, a second explosion hits. Rescue operation and mass evacuations start.

8.20am: Rail transport to airport stopped and road closures brought in.

8.40am: Airport confirms explosions and urges people to stay away from the area.

9.10am: Blast reported on train at Maelbeek/Maalbeek Metro station, near European Commission headquarters.

9.27am: Brussels Metro system closed.

10am: Entire public transport system including buses, trams and trains shut down. Belgian Crisis Centre tweets: “Stay where you are.”

11.50: Belgian federal prosecutor confirms that three explosions – two at airport and one at Maelbeek station – were terrorist attacks. At least one is thought to be a suicide bombing. Criminal investigation launched.

Authorities did not immediately confirm how many people died at the airport but the VRT News quoted officials saying at least 13 had died and 35 were injured.

Brussels' STIB transport authority said that at least 15 people were killed and 55 wounded at Maalbeek station but warned that the toll was “provisional”.

Zach Mouzoun, who arrived on a flight from Geneva about 10 minutes before the first blast, told France's BFM television that the second explosion brought down ceilings and ruptured pipes, mixing water with blood from victims.

“It was atrocious,” he said. “There was blood everywhere, injured people, bags everywhere. We were walking in the debris. It looked like a war zone.”

A view of the train after the explosion in Maelbeek station in Brussels (Corbis)

Footage showed passengers running from the terminal building as smoke poured through smashed windows.

The airport, which was evacuated, was closed to all departures and arrivals on Tuesday and Brussels residents were being urged to stay at home amid security operations across the city.

Brussels has been under increased security measures since November's Paris attacks and has seen several operations in recent weeks linked to the hunt for Salah Abdeslam, who was caught on Friday.

Airports across Europe were increasing precautions, including at Gatwick and Heathrow, which said there would be a “high visibility” police presence.

The Foreign Office is advising British citizens to follow the instructions of Belgian security services and to remain vigilant in crowded areas.