Belgian synagogues are reported to be under armed police guard as the death toll rises to four killed in the attack on the Jewish Museum in Brussels.
The hunt for the lone gunman involved in the shooting continues.
Two of the dead have been identified as a couple in their 50s from Tel Aviv visiting Belgium as tourists.
The third person killed was a museum volunteer.
A second volunteer died later in hospital.
The four victims were hit in the face and neck when a lone gunman attacked the museum on Saturday afternoon before fleeing.
A man arrested by police was later released and is being regarded as a witness rather than a suspect.
The head of the Belgian League Against Antisemitism, Joel Rubinfeld told the AFP news agency that the shooting was a result of the “climate of hate” in the country.
Speaking to the press at the scene, Belgian Interior Minister Joelle Milquet said: “Two women and one man are dead, a third person is in hospital.”
The Interior Minister said it was too early to say if the shooting was motivated by antisemitism but that there were “strong grounds for presuming so”.
According to the La Libre newspaper, the shooter drove up and parked next to the museum. He then got out of the car, placed two bags on the ground and opened fire on bystanders.
Belgium’s Foreign Minister Didier Reynders said he was “shocked by the murders committed at the Jewish Museum”.
The museum, in the Sablon district of central Brussels, is not run by the local Belgian Jewish community, so it is open on Saturdays and there were visitors present at the time of the killings.
The shooting comes as Belgium prepares for a number of new election results, including for its federal government, the country’s regional parliaments, and the European Parliament vote which took place last Thursday.
The attack was condemned by Israeli prime minister Benjamin Netanyahu, who blamed it on "slander and lies against the state of Israel".
"This act of murder is the result of constant incitement against Jews and their state," he said.
The president of the European Jewish Congress Dr Moshe Kantor called on European governments to enact tougher legislation against antisemitism and to increase security at Jewish institutions in the wake of the attack.
In a statement he said: "The EJC has been warning for over two years, since the murderous terror attack at the Jewish school in Toulouse, that such acts will continue if no additional resources are put into place to guarantee the security of our communities.
"We demand that our communities are protected. It is our basic right as European citizens to go about our daily lives in full security."
The World Jewish Congress described the attack as “a heinous act of terror that clearly was targeted at Jews”.