Multiple blasts in Brussels: City in lockdown, 21 dead

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At the Brussels airport, two explosions splattered blood across the departure lounge and collapsed the ceiling. Witnesses said that one occurred at an excess baggage payment counter and the other near a Starbucks cafe. All flights were canceled, arriving planes and trains were diverted and Belgium's terror alert level was raised to its highest level. Authorities told people in Brussels to stay where they were, bringing the city to a standstill. Airport security was also tightened in Paris, London and other European cities.

Emergency personnel are seen at the scene of a blast outside a metro station in Brussels, in this still image taken from video on March 22, 2016. (Source: REUTERS/Reuters TV)

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European security officials have been braced for a major attack for weeks, and warned that the Islamic State group was actively preparing to strike. Abdeslam's arrest on Friday heightened those fears, as investigators said many more people were involved in the Nov. 13 attacks that killed 130 people in Paris than originally thought, and that some are still on the loose.

People leave the scene of explosions at Zaventem airport. (Source: Reuters)

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In this photo provided by Georgian Public Broadcaster and photographed by Ketevan Kardava a man is wounded in Brussels Airport in Brussels, Belgium, after explosions were heard Tuesday, March 22, 2016. (Source: Ketevan Kardava/ Georgian Public Broadcaster via AP)

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In this photo provided by Georgian Public Broadcaster and photographed by Ketevan Kardava two women wounded in Brussels Airport in Brussels, Belgium, after explosions were heard Tuesday, March 22, 2016. (Source: Ketevan Kardava/ Georgian Public Broadcaster via AP)

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Near the entrance to the Maelbeek subway station, not far from the headquarters of the European Union, rescue workers set up a makeshift treatment center in a pub. Dazed and shocked morning travelers streamed from the metro entrances as police tried to set up a security cordon.

Emergency personnel are seen at the scene of a blast outside the station. (Source: Reuters)

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The explosions at the airport hit at the middle of the busiest time there. Smoke was seen billowing out of the terminal. (Source: REUTERS)

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Belgian media reported 13 people were killed at the airport. It was not clear whether any died in the metro explosion.

A victim is evacuated by emergency services after the explosion on metro station.

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People react as they walk away from Brussels airport after explosions rocked the facility. (AP Photo)

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Injured people are seen at the scene of explosions at Zaventem airport near Brussels. (Source: Reuters)

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In this image made from video, emergency rescue workers stretcher an unidentified person at the site of an explosion at a metro station in Brussels, Belgium, March 22, 2016. Explosions rocked the Brussels airport and the subway system Tuesday, just days after the main suspect in the November Paris attacks was arrested in the city, police said.(APTN via AP)

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The blasts have left many people outside the airport shaken, with some reduced to tears. (Source: AP)

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People comfort each other after being evacuated from Brussels airport, after explosions rocked the facility in Brussels, Belgium, Tuesday March 22, 2016. (Source: AP Photo/Geert Vanden Wijngaert)

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People react outside Brussels airport after explosions rocked the facility in Brussels, Belgium Tuesday March 22, 2016. (Source: AP Photo/Geert Vanden Wijngaert)