Belgian authorities are searching for an armed man who killed three people and injured a fourth at the Jewish Museum in Brussels.
Two of the three victims of Saturday's attack were Israeli tourists from Tel Aviv, a spokesman for the Israeli Foreign Ministry told the AFP news agency on Sunday.
Belgian officials released a thirty-second video clip from the museum's security cameras showing a man wearing a dark cap and a blue jacket enter the building, take a Kalashnikov rifle out of a bag, and shoot into a room, before walking out.
Deputy prosecutor Ine Van Wymersch said on Sunday that the suspect "probably acted alone, was armed and well prepared". He said he could not confirm whether the shooting was a "terrorist or anti-Semitic act" and added that all leads remained open.
Israel's foreign minister and prime minister condemned the shooting, saying it was the result of "anti-Israeli and anti-Semitic incitement".
The European Jewish Congress called for greater security at Jewish institutions and tougher legislation in dealing with anti-Semitic crime.
In a statement issued on Sunday, Moshe Kantor said: "Such acts will continue if no additional resources are put into place to guarantee the security of our communities, to share intelligence and law enforcement cooperation and tougher punishments.
"How many more deadly attacks at Jewish institutions does our community need to endure until European governments get serious with a climate of increasing hate towards Jews?"
Belgian officials, including the foreign minister, have expressed their shock at the crime.
On Sunday, the French interior minister Bernard Cazeneuve said two Jewish men were attacked as they left a synagogue in Creteil, southeast of Paris, on Saturday night. He ordered more security around Jewish and Israeli establishments.