BRUSSELS >> Belgian police early Tuesday hunted for a gunman with suspected extremist motives who killed two Swedes with stunning viciousness before disappearing into the night. He created such fear that authorities shut down a Belgium-Sweden soccer match and held 35,000 fans inside for several hours as a precaution.

Eric Van Duyse, spokesman for the federal prosecutor’s office, said the investigation was centering on “a possible terrorist motivation for the shooting” after “a claim of responsibility was posted on social media.”

“This person claims to be inspired by Islamic State,” Van Duyse said. “The Swedish nationality of the victims was put forward as the probable motive.” Sweden raised its terror alert to the second-highest level in August after a series of public Quran-burnings by an Iraqi refugee living in Sweden resulted in threats from Islamic militant groups.

“At this time, no element indicates a possible link with the Israeli-Palestinian situation,” Van Duyse said, offering scant relief on a continent where many nations have increased their vigilance for fear of attacks linked to the Israel-Hamas war.

In Belgium, the anti-terror center said the terror alert in the capital was raised to its top rating of 4, meaning a “threat is extremely serious.” It previously stood at 2, which means the threat was average. The alert level or the rest of the country was raised to 2.

“I have just offered my sincere condolences to @SwedishPM following tonight’s harrowing attack on Swedish citizens in Brussels,” Prime Minister Alexander De Croo De Croo said. He added on X, formerly known as Twitter, “As close partners the fight against terrorism is a joint one.”

As for the soccer match, Van Duyse said, “security measures were urgently taken to protect the Swedish supporters” at the game in the national stadium not far from the schooting.

Over two hours after the game was suspended, a message flashed on the big stadium screen saying, “Fans, you can leave the stadium calmy.” Stand after stand emptied onto the streets filled with police as the search for the gunman continued.

“Frustrated, confused, scared. I think everyone was quite scared,” said Caroline Lochs, a fan from Antwerp.

Interior Minister Annelies Verlinden said, “A horrible shooting in Brussels, and the perpetrator is actively being tracked down.”

Media reports aired amateur videos showing a man arriving on a scooter in an orange fluorescent vest, dropping the vehicle and immediately taking out a large weapon and opening fire on passersby. Apart from the two Swedes who were killed, a local taxi driver was hurt but his life was not in danger.

The attacker then picked up his scooter and sped off into the gathering darkness.

Even though only two people died in the attack, compared to dozens and dozens in extremist attacks in past years in Europe, the return of a sense of dread was immediate.

“Horrified at the indiscriminate killing in the heart of #Brussels tonight,” said European Parliament President Roberta Metsola. “Terror and extremism cannot infiltrate in our societies. People must feel safe. Hate will not win.”