The scene of the shooting at the Jewish Museum of Brussels. Photo: Screenshot.

Belgian prosecutors announced on Monday that they are treating Saturday’s deadly shooting at the Jewish Museum of Belgium as a terrorist attack. Four people, including two Israelis, were killed in the assault.

The investigation will now be handled by federal rather than regional prosecution, Bloomberg reported.

“The analysis of the camera images shows that we are dealing with an individual acting in cold blood and who is very determined in his actions,” Ine Van Wymersch, a spokeswoman for the Brussels prosecution office, told journalists in the Belgian capital. “The identification of the victims and their nationalities is a complementary element” in deciding that the case should be elevated to a national level, she said.

Investigators on Sunday released video footage showing the unidentified killer entering the Jewish Museum, removing an assault rifle from a bag, firing it and then leaving the scene on foot. Witnesses described the attacker as young, Bloomberg reported.

Police detained one suspect late Saturday but he was subsequently released and is now considered a witness, according to NBC News.

“We call on the whole population to help identify this person,” Wymersch said. A Brussels police spokesperson added, “We are studying the film. Everything is being done to find him,” the U.K.’s Express noted.

A number of Jewish groups responded to the shooting by calling for European leaders to take more vigorous action against rising anti-Semitism on the continent. Israeli Prime Minister Benjamin Netanyahu condemned the attack and said it was the result “of endless incitement against Jews and their state.”A similar assertion was made by Israeli Foreign Minister Avigdor Lieberman.