1/18People react as they walk away from Brussels airport after explosions rocked the facility in Brussels, Belgium, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
2/18People leave the scene of explosions at Zaventem airport near Brussels, Belgium, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
3/18Broken windows seen at the scene of explosions at Zaventem, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
4/18People leave the scene of explosions at Zaventem airport near Brussels, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
5/18People react as they walk away from Brussels airport after explosions rocked the facility in Brussels, Belgium March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
6/18Ambulances arrive to the scene at Brussels airport, after explosions rocked the facility in Brussels, Belgium, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
7/18In this image made from video, emergency rescue workers stretcher an unidentified person at the site of an explosion at a metro station in Brussels, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
8/18A victim receives first aid by rescuers, on March 22, 2016 near Maalbeek metro station in Brussels, after a blast at this station near the EU institutions caused deaths and injuries.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
9/18Passengers evacuating the Brussels Airport of Zaventem, after a string of explosions rocked Brussels airport and a city metro station, killing at least 21 people, as Belgium raised its terror threat to the maximum level, March 22, 2016
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
10/18Policemen speak at a security perimeter near Maalbeek metro station, on March 22, 2016 in Brussels, after a blast at this station near the EU institutions caused deaths and injuries.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
11/18A woman is evacuated in an ambulance by emergency services after a explosion in a main metro station in Brussels, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
12/18Policemen stand guard at the entrance of a security perimeter set near Maalbeek metro station, on March 22, 2016 in Brussels, after a blast at this station near the EU institutions caused deaths and injuries.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
13/18People comfort each other after being evacuated from Brussels airport, after explosions rocked the facility in Brussels, March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
14/18Firefighters arrive at the scene near Maalbeek metro station, on March 22, 2016 in Brussels, after a blast at this station near the EU institutions caused deaths and injuries.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
15/18A private security guard helps a wounded women outside the Maalbeek metro station in Brussels on March 22, 2016 after a blast at this station located near the EU institutions.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
16/18People leave candles and flowers in tribute to victims of triple bomb attacks in front of the stock exchange building in the city center of Brussels on March 22, 2016.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
17/18Belgium Attacks
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
18/18Flowers, a candle and a letter with the words 'Defy Terror' - ' Preserve Freedom' are placed in front of the Belgian Embassy in Berlin, Germany, March 22, 2016 after the attacks in Brussels.
At least three explosions rocked Brussels Tuesday morning - two at the airport and one at a metro station in the heart of the capital, with local media reporting more than 20 dead and many others injured in the airport blasts.
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All railway stations in Brussels have been shutdown amid Tuesday's deadly bombings at the city's airport and a subway station.
The Belga news agency says shots were fired and words shouted in Arabic before the first two explosions at the airport's departure hall, which shattered the building's windows.
An hour later, several other people were wounded in an explosion at the Maalbeek subway station near the main headquarters of the European Union. EU personnel have been told to either stay in their offices or at home.
Reports of fatalities from the triple bombings have varied amid the chaos. Public broadcaster VRT says at least 13 people were killed and at least 35 others wounded in the first two explosions at the airport's departure hall, while broadcaster VTM has been reporting that as many as 10 people are dead after the Maalbeek blast.
All flights in and out of the airport have been cancelled, and Brussels' entire subway system has been shutdown as well. Belgian authorities have raised the nation's terror alert level to its maximum level.
Authorities in Frankfurt, London, Paris and Holland have boosted security at their airports in response to the Brussels' bombings.
Tuesday's explosions occurred days after Belgian police arrested Salah Abdeslam, the prime suspect man last November's terrorist attacks in the Paris that left 130 people dead and more than 300 wounded.