Vincent Kessler/Reuters
  • A woman reacts during a minute of silence held at a memorial in front of Brussels' Stock Exchange on Place de la Bourse (Beursplein), March 24, 2016.
    Philippe Huguen/AFP/Getty Images
  • A child looks on during a vigil at the Belgium Consulate, March 23, 2016, in Montreal, to mourn the victims of the attacks that occurred in Brussels.
    Paul Chiasson/The Canadian Press, via AP Photo
  • People look at messages written in chalk on a wall on the Place de la Bourse (Beursplein) in central Brussels, March 24, 2016, in tribute to the victims of the Brussels attacks.
    Patrik Stollarz/AFP/Getty Images
  • People attend a street memorial service near the old stock exchange in Brussels following Tuesday's bomb attacks in Brussels, Belgium, March 23, 2016.
    Vincent Kessler/Reuters
  • A woman holding a Belgian flag joins in singing and chanting at the Place De La Bourse in honor of the victims of terrorist attacks on March 23, 2016 in Brussels.
    Christopher Furlong/Getty Images
  • Employees at Zaventem airport take part in a silent walk to commemorate the victims of a terrorist attack in Brussels, March 23, 2016.
    Olivier Hoslet/EPA
  • Teresa Mancheno, center, a maintenance worker at Newark Liberty International Airport, prays during a vigil honoring the victims of the attacks in Belgium, March 23, 2016, in Newark, N.J.
    Julio Cortez/AP Photo
  • A woman and two children visit a memorial for the victims of the bombings at the Place de la Bourse in the center of Brussels, March 23, 2016.
    Martin Meissner/AP Photo
  • Belgium's King Philippe and firefighters lay a wreath in front of the damaged Zaventem Airport terminal in Brussels, March 23, 2016.
    Frederic Sierakowski/Pool/AP Photo
  • Visitors to the Washington Monument walk under flags flying at half-staff early Wednesday, March 23, 2016, honoring the victims of the Brussels attacks, in Washington. In the background is the Lincoln Memorial.
    J. David Ake/AP Photo
  • People light candles during a memorial ceremony at Hanoi Tower in Hanoi, Vietnam, March 23, 2016, in tribute to victims in terrorist attack in Brussels.
    Luong Thai Linh/EPA
  • People light candles and offers flowers asking for the "Justice for Brussels" during a memorial event along a main street in Quezon city, metro Manila, Philippines, March 23, 2016.
    Romeo Ranoco/Reuters
  • Flowers and candles are seen on the steps at the Belgian embassy in tribute to victims of Tuesday's attacks in Brussels in Berlin, Germany, March 23, 2016.
    Fabrizio Bensch/Reuters
  • People hold a minute of silence around a makeshift memorial at Place de la Bourse in Brussels, March 23, 2016.
    Kenzo Tribouillard/AFP/Getty Images
  • A man reacts at a street memorial following Tuesday's bomb attacks in Brussels, March 23, 2016.
    Francois Lenoir/Reuters
  • Supporters for victims of the Brussels terrorist attacks gather to show their solidarity during a vigil and moment of silence in San Francisco, Calif., March 22, 2016.
    Monica Davey/AFP/Getty Images
  • The colors of the Belgian flag are projected on the courthouse in Lyon, France, in tribute to the victims of today's Brussels bomb attacks, March 22, 2016.
    Robert Pratta/Reuters
  • A young girl lights a candle at the Place de la Bourse following today's attacks, March 22, 2016 in Brussels.
    Carl Court/Getty Images
  • Ukrainian servicemen hold torches in front of floral tributes during a ceremony to honor the victims of the Brussels attack in front of the Belgian embassy in Kiev, March 22, 2016.
    Anatolii Stepanov/AFP/Getty Images
  • People hold up a banner as a mark of solidarity at the Place de la Bourse following the attacks on March 22, 2016 in Brussels, Belgium.
    Carl Court/Getty Images
  • A woman lights a candle as people gather to leave tributes at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium.
    Carl Court/Getty Images
  • Two soldiers from the Belgian Army patrol outside EU headquarters as EU flags fly at half mast after explosions in Brussels on March 22, 2016.The attack prompted a lockdown of the Belgian capital.
    Virginia Mayo/AP Photo
  • Floral tributes, candles, notes and a drawing by French cartoonist Plantu are displayed at the Place de la Republique in Paris in tribute to the victims of the Brussels attack, March 22, 2016.
    Joel Saget/AFP/Getty Images
  • A local holds a paper national flag of Belgium at Beursplein square following the attacks on March 22, 2016 in Brussels, Belgium.
    Alexander Koerner/Getty Images