Updated — May 25, 2:00 p.m. ET:
Four people were killed on Saturday in a shooting at the Brussels Jewish Museum. Police detained one suspect who was at the scene late Saturday, but he was released and is now considered a witness.
Images released by Belgian police show that the gunman wore a cap and blue shirt. He carried two bags over his shoulder.
Although the motive remains unknown, Belgian Foreign Minister Didier Reynders says "you cannot help to think that when we see a Jewish museum, you think of an anti-Semitic act." Anti-terror measures have been ordered for Jewish sites around Belgium.
The Belgian Prime Minister, Elio Di Rupo, confirmed the shooting and tweeted his condolences.
Shocked by the events in Brussels. My sincere sympathy and support for the families and loved ones of the victims