The Belgian Federal Police released surveillance video of three men suspected of taking part in the attacks at Belgium's Zaventem Airport, including the "man in the hat." AP hide caption

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Mohamed Abrini (top right) is seen with Salah Abdeslam in this image taken from a CCTV camera at a gas station north of Paris on Nov. 11, 2015. Wanted for questioning over both the Paris attacks and the recent bombing of the Brussels airport, Abrini was arrested Friday. AFP/Getty Images hide caption

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Police detain a group of people at the Place de la Bourse in Brussels, Belgium, Saturday. Authorities had banned all marches in Brussels after a far-right group announced its plans to hold an anti-Muslim rally in the city. Geert Vanden Wijngaert/AP hide caption

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A masked man raises a fist and the Belgian flag outside the stock exchange in Brussels on Sunday, at a square filled with memorials to the victims of Tuesday's terrorist attacks. Tensions mounted after the square, occupied by mourners, was invaded by far-right protesters whom AFP identified as football hooligans. Patrik Stollarz/AFP/Getty Images hide caption

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The Belgian flag flies at half-mast at the Koningin Astrid-Reine Astrid military hospital in Brussels on March 24, 2016. Some of the people wounded in the Brussels attacks are being treated there. Patrik Stollarz/AFP/Getty Images hide caption

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People gather Friday at a makeshift memorial in tribute to the victims of the Brussels terror attacks, on Place de la Bourse square in Brussels. Grieving Belgians held prayers in the rain for the victims, but there was also growing anger at the government for letting a string of militants slip through the net. Laurie Dieffembacq/AFP/Getty Images hide caption

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Ibrahim el-Bakraoui (center) appears in this image provided by the Belgian Federal Police in Brussels, on March 22. Turkish authorities say they warned both Belgium and the Netherlands of his terrorist links when Turkey deported him last year. AP hide caption

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U.S. Secretary of State John Kerry stands alongside Belgian Prime Minister Charles Michel during a meeting in Brussels on Friday. Laurie Dieffembacq/AFP/Getty Images hide caption

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Policemen search passengers at the entrance of the De Brouckere metro station in Brussels on March 24, two days after the terrorist attack on the city. PHILIPPE HUGUEN/AFP/Getty Images hide caption

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Investigation Continues As Brussels Recovers From Terror Attacks
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Police patrol outside the council chamber of Brussels on Thursday during ongoing investigations into the Paris and Brussels terrorist attacks. More than 30 people have been identified as being involved in a network behind the Paris attacks on Nov. 13, with links now established to this week's bombings in Brussels. Dirk Waem/AFP/Getty Images hide caption

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Brussels Unites In Grief As Search For Attacker — Or Attackers — Continues
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Passengers wait to check in at Chicago's O'Hare International Airport in June 2015. TSA screenings at U.S. airports are beyond ticket counters, baggage claim and other heavily trafficked areas. After terrorist bombings at the Brussels airport targeted those areas, U.S. officials are reconsidering how to keep them safe. Scott Olson/Getty Images hide caption

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Officials Consider How U.S. Airports Could Stop A Brussels-Style Attack
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This image provided by the Belgian Federal Police shows a man at Belgium's Zaventem airport whom officials have identified as Ibrahim el Bakraoui. A Belgian prosecutor named him as a suspected suicide bomber in Tuesday's attack on the airport. AP hide caption

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A Libyan fireman stands in front of a flaming oil storage tank in northern Libya's Ras Lanouf region on Jan. 23. It was set alight in fighting with the Islamic State, which has established a strong presence in the country and taken control of the city of Sirte. AFP/Getty Images hide caption

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A man wears the Belgian flag as people observe a minute of silence Wednesday at the Place de la Bourse, in honor of the victims of Tuesday's terrorist attacks in Brussels. Christopher Furlong/Getty Images hide caption

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Brussels Attacks, One Day After: What We Know
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People walk away from Brussels airport after Tuesday's terrorist attack. Analysts say the violence may reduce travel for a while but the industry should bounce back. Geert Vanden Wijngaert/AP hide caption

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