A suspect in the killing of two Swedish nationals in Brussels on Monday evening, in what officials called an act of terrorism, was fatally shot by the police on Tuesday morning after an overnight search, the office of Belgium’s public prosecutor said.
The suspect, a man whose name was not released, died in a hospital, the prosecutor’s office said. A weapon was found at the scene after the man was shot, according to the interior minister.
Belgium’s justice minister, Vincent Van Quickenborne, said on Tuesday that the suspect, a Tunisian man who was living in the country illegally, had been known to the authorities for possible radicalization and criminal activity since 2016, but the authorities had not acted on mounting intelligence that he posed a threat.
The shooting in central Brussels on Monday evening, before a scheduled soccer match between Sweden and Belgium, was described as terrorism by Prime Minister Alexander De Croo. It shocked the Belgian capital, which has a painful history of terrorist attacks. Islamic State militants carried out bombings there in 2016 that killed more than 30 people and wounded hundreds more.
“I have just offered my sincere condolences to @SwedishPM following tonight’s harrowing attack on Swedish citizens in Brussels,” Mr. de Croo said on X on Monday, referring to the Swedish prime minister. “Our thoughts are with the families and friends who lost their loved ones. As close partners the fight against terrorism is a joint one.”
The victims were wearing Sweden soccer shirts and may have been preparing to attend the game at a stadium in northern Brussels. The game was suspended after the shooting, but several hours passed before fans at the stadium were allowed to leave.
An unverified video of the attack circulating on social media showed a man in a white helmet and a high-visibility orange jacket pursuing and shooting at his victims, who ran into a building, and then shooting them again at closer range.
Another unverified video circulating on social media, shot in selfie mode, showed a man in a jacket very similar to the one worn by the gunman in the other video, speaking in Arabic and describing himself as an adherent of the Islamic State.
“So there has been a claim via social media where someone says he is the perpetrator, that he has sympathies for I.S., and what is also important, he mentions the Swedish nationality of those victims,” Eric Van Der Sypt, a spokesman for the federal prosecutor’s office, told the Belgian broadcaster VTM.
“For now, at the current stage of the investigation, there would be no relationship to the conflict in Gaza,” Mr. Van Der Sypt added. The bloodshed in Israel and Gaza since the Hamas attack of Oct. 7 has raised concerns in many countries that sympathizers with one side or the other might carry out violent acts.
Mr. Van Der Sypt, in comments to the news agency Belga, said that a third man, a taxi driver, had been wounded in the attack but was being treated in a hospital and was out of danger.
The threat level in Brussels was raised after the attack, and France has tightened controls at its border with Belgium, France’s interior minister, Gérald Darmanin, said.
While the suspect’s identity was not formally released, Belgian news outlets identified him as Abdesalem Lassoued, a 45-year-old man originally from Tunisia.
The Belgian authorities’ handling of the man’s activities was coming under closer scrutiny on Tuesday after the acknowledgment that he had been known to the police and even flagged for potential terrorist activity seven years ago.
Mr. Van Quickenborne, the justice minister, told a news conference that the authorities had received an alert from a foreign police service in July 2016, claiming that the man was radicalized.
“There were countless reports like that at the time, dozens of reports of that nature per day,” Mr. Van Quickenborne said. “That information was then investigated, and nothing further could be done with it.”
But the minister said that the suspect had been on the authorities’ radar since that first red flag, for suspicions of human smuggling and for illegally living in Belgium, among other things. In June last year, the minister said, he had been flagged to a special task force for suspicious behavior at a mosque, but that “did not trigger any further action.” Mr. Van Quickenborne noted.
This year, the minister added, the suspect was said to have threatened a resident of an asylum center on social media after the resident reported that the suspect had been convicted over terrorist activities in Tunisia.
The Belgian authorities have also failed to thwart earlier terrorist threats. Several of the Islamic State attackers who carried out the November 2015 attacks in Paris that killed more than 100 people had been based in Belgium and were known to the authorities.
The Belgian capital is home to the leading institutions for the European Union as well as NATO headquarters.
The European Commission, which employs thousands of people, urged employees after the attack to work from home on Tuesday, and said that it would keep the schools and day care centers for the staff’s children closed.
In a post on X, Charles Michel, the president of the European Council, said that “the heart of Europe is hit by violence.”
Koba Ryckewaert contributed reporting from Brussels, and Liam Stack from New York.