Belgium stands “united” against the “abhorrent” attack Saturday at the Brussels Jewish Museum that killed three people and critically injured one, Belgian Prime Minister Elio Di Rupo said hours after the shooting.

“Our country and all Belgians, no matter their language, origins or [religious] convictions, are united in the face of this abhorrent attack on a Jewish cultural center,” said the Belgian leader, adding that “all efforts are in place” to identify and arrest those who committed the crime.

One man was in custody after the attack and police were looking for a second person, according to Belgian authorities.

“A person left the scene in their vehicle. We have identified and arrested them. But we do not know if they have a link to the events,” a prosecution spokeswoman told a news conference, adding that the person was being “heard as a suspect.”

The three dead were two women and a man, and they were hit by bullets in the throat and face, said Ine Van Wymersch, spokeswoman for the prosecutor’s office. No further details were given.

Van Wymersch said one suspect was detained after he drove away from the museum around the time of the attack. A second person suspected of being implicated apparently walked away from the scene.

The murders Saturday afternoon were a result of “a climate of hate,” said Joel Rubinfeld, the head of the Belgian League against anti-Semitism.

Rubinfeld told AFP it clearly “is a terrorist act” as a man had been seen driving up and entering the museum before opening fire inside and running off.

European Jewish Congress President Moshe Kantor said that, even though it has yet to be established whether the attack was anti-Semitic, “we are acutely aware of the permanent threat to Jewish targets in Belgium and across the whole of Europe.”

“European governments must send out a clear message of zero tolerance towards any manifestation of anti-Semitism,” Kantor said in a statement.

One person remained in critical condition as a result of the shooting. Twelve people were treated for shock, according to local sources.

“Two women and one man are dead, a third person is in hospital,” Interior Minister Joelle Milquet said at the scene. “We don’t yet know if they were tourists or staff, they haven’t been identified.”

Asked whether she believed it was an anti-Semitic attack, she said it was too early to say as a police and judicial inquiry was under way but that given the target “there are strong grounds for presuming so”.

Milquet said the government had moved to increase protection at Jewish buildings as well as the Israeli embassy.

The country’s foreign minister, Didier Reynders, tweeted Saturday that he was “shocked by the murders committed at the Jewish museum.”

“I am thinking of the victims I saw there and their families,” he said.

The La Libre newspaper said on its website that an Audi had driven up and parked outside the museum, and that both a passenger and the driver had gotten out.

It said the driver placed two bags on the ground and then opened fire on bystanders before driving off.

“A person wearing a backpack was seen opening fire before fleeing,” Radio Télévision Belge Francophone (RTBF) reported [in French].

Police and emergency services were at the site, which had been cordoned off.

Policemen stand guard around the site of a shooting near the Jewish Museum in Brussels, on May 24, 2014. Three people were killed and one badly injured in a shoot-out Saturday near the Jewish Museum in Brussels city centre. Photo credit: AFP/Belga/ Nicolas Maeterlinck)

Policemen stand guard around the site of a shooting near the Jewish Museum in Brussels, on May 24, 2014. Three people were killed and one badly injured in a shoot-out Saturday near the Jewish Museum in Brussels city center. (photo credit: AFP/Belga/Nicolas Maeterlinck)

The Jewish Museum of Belgium, which was not answering calls, is located in the heart of the Sablon district which is home to the city’s top antique dealers. The area is a popular weekend haunt for shoppers.

The museum is not run by the Jewish community, and is therefore open on Saturdays. There were visitors at the museum at the time of the shooting.

The head of Belgium’s Jewish Consistory told La Libre that it was “probably a terrorist act. For us it is an extremely serious act.”

He said the museum had received no recent threats and that its staff “are in shock.”

The police had received a “serious tip,” he added, amid reports that a bystander had given the police the car’s registration number.

The Sablon area consists of cobbled streets with numerous antique shops, trendy cafes and museums, including the Jewish Museum. The attack happened during a three-day jazz festival in the neighborhood, and came on the eve of national and European Parliament elections.

Viviane Teitelbaum, a Jewish member of the Brussels legislature, said anti-Semitic attacks reached a peak in the early 1980s but had dropped off before a recent rise in anti-Jewish sentiment.

“It has been a very difficult place to live” for Jews, she said, adding that many young people are leaving the country. She added that some 40,000 Jews live in Belgium, half of them in Brussels.

In the ADL’s recent survey of anti-Semitism, Belgium was said to have a 27 percent score for anti-Semitic attitudes, with one in three Belgians saying that Jews think they are better than other people and 44% saying Belgian Jews were more loyal to Israel than to Belgium.