Police officers work at the area of shooting near the Jewish Museum in Brussels, Belgium, 24 May 2014. (Olivier Hoslet/EPA)

Three people were killed and one seriously injured in a spree of gunfire at the Jewish Museum in Brussels on Saturday, officials said. Police detained one suspect who was at the scene and were looking for a second.

The attack, which came on the eve of national and European Parliament elections, led officials to elevate anti-terrorist measures. Prime Minister Elio Di Rupo immediately expressed support for the Jewish community.

“All Belgians are united,” he said.

Belgian Foreign Minister Didier Reynders, who was in the vicinity, said the scene “was terrible and left me shocked” as he saw two of the three dead lying at the entry of the museum, located in the affluent Sablon neighborhood.

Reynders added that “you cannot help but think that when we see a Jewish museum, you think of an anti-Semitic act. But the investigation will have to show the causes.”

Interior Minister Joelle Milquet told reporters that the shooter apparently parked a car outside before entering the Jewish Museum. She added that the gunman “apparently fired rather quickly, went outside and left.”

Milquet said anti-terrorism measures had been immediately heightened. “We decided to apply a maximum level of protection to Jewish sites,” she said.

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 government must send out a clear message of zero tolerance toward any manifestation of anti-Semitism,” Kantor said in a statement.

The mid-afternoon attack occurred in the fashionable Sablon area, which was hosting a three-day jazz festival and is usually clogged with tourists and shoppers on weekends.

Viviane Teitelbaum, a 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 said that about 40,000 Jews live in Belgium, half of them in Brussels.

In France, President François Hollande condemned the “horrifying killings with the greatest force.” In a statement, he expressed France’s solidarity with neighboring Belgium and offered condolences to the families of victims.

Associated Press