BRUSSELS, Belgium -- Three people were shot dead and a fourth seriously wounded in an armed attack at the Jewish Museum in Brussels on Saturday, officials said. Police detained one suspect and were looking for a second.

The bloodshed, which came on the eve of national and European Parliament elections, led officials to immediately raise anti-terror measures.

Belgian Foreign Minister Didier Reynders, who was in the vicinity, said the scene "was terrible and left me shocked" as he saw the bodies of two of the victims lying at the entrance of the museum, located in the swanky Sablon neighbourhood of Belgium's capital.

Reynders said that "you cannot help to 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 the gunman "apparently fired rather quickly, went outside and left."

The three dead were two women and a man, and all were struck by bullets in the face or throat, 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 being sought for questioning left the area on foot. Van Wymersch said security camera footage was being studied to try to identify the person.

Prime Minister Elio Di Rupo expressed support for the Jewish community, and said "everything has been mobilized that can be mobilized" to bring the killer or killers to justice.

"All Belgians are united," he said.

A statement issued by the office of Israeli Prime Minister Benjamin Netanyahu condemned the attack and said, "This act of murder is the result of constant incitement against Jews and their state."

Milquet said anti-terror measures had immediately been heightened as a precaution. "We decided to apply to 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 governments must send out a clear message of zero tolerance toward any manifestation of anti-Semitism," Kantor said in a statement.

The attack, which took place shortly before 4 p.m., occurred in the Sablon area, which was hosting a three-day jazz festival and is usually clogged with tourists and shoppers on weekends. It has cobblestone streets with numerous antique shops, trendy cafes and museums, including the Jewish Museum.

Police cordoned off several streets around the museum with blue-and-white police tape, and numerous ambulances and police vans were at the scene.

Viviane Teitelbaum, a member of the Brussels legislature, said anti-Semitic attacks reached a peak in the early 1980s but had dropped off, but she noted 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 some 40,000 Jews live in Belgium, half of whom reside in Brussels.

Simone Susskind, another Brussels politician, said the museum has been at its current site for around a decade, after moving from an old synagogue in southern Brussels. She said her late husband David was a driving force behind the museum's creation, believing that as home of the European Union and self-proclaimed "capital of Europe," Brussels needed a museum to recount the history of Belgium's Jewish community.

In neighbouring France, President Francois Hollande condemned the "horrifying killings with the greatest force." In a statement, he expressed France's solidarity with Belgium and offered condolences to the families of the victims.