An unidentified government official said that a young Belgian man, reported to have worked at the reception of the museum, died on Sunday of wounds sustained in the attack, in which three other people were killed on the spot.

Belgium's federal police agency released three videos of the attack and asked for the public's help in bringing him to justice.

The gunman who carried out Saturday's attack was described as being of medium build and athletic. One of the videos appears to show him firing a rifle in the building before running out.

Two Israeli tourists and a French woman died immediately after the attack, which occurred on Saturday afternoon at the museum in the popular tourist district of Sablon in the inner city.

The museum says it has no information on the possible motive, but investigators have been examining whether the shooting was motivated by anti-Semitism.

International outrage

In Israel, the attack has been denounced as a racist hate crime, with Prime Minister Benjamin Netanyahu expressing concern at what he called "growing anti-Semitism in Europe."

French President Francois Hollande also said there was "no doubt" the attack was motivated by anti-Semitism.

Belgian Prime Minister Elio Di Rupo spoke with both Hollande and Netanyahu on Sunday to express his condolences for the deaths of their nationals.

"The heinous attack in the Jewish Museum of Belgium is an attack against the Jewish community and an attack against the values of our democracy," a statement from Di Rupo's office said.

Security was tightened at Jewish religious and cultural sites in Belgium after the shooting.

The attack came just hours before Belgians were due to head to the polls for parliamentary and European elections in which far-right parties were expected to make gains.

tj/lw (dpa, AP)