Police hunt for the gunman as a man claiming to be from ISIL (ISIS) releases video saying he was behind the attack.

Belgian police were searching for a gunman who shot dead two Swedish nationals and injured a third person in Brussels as a man who identified himself as a member of the ISIL (ISIS) group claimed responsibility for the attack in a video posted online.

The suspect fled the scene after the shooting on Monday night.

Eric Van Duyse, a spokesman for the federal prosecutor’s office, said the investigation was focused 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 threat alert to the second-highest level in August, warning of an increase in threats against Swedish interests abroad after the burning of the Quran by an Iraqi refugee in Sweden outraged Muslims and led to threats from hardline groups.

Belgian Prime Minister Alexander de Croo confirmed on social media platform X, formerly known as Twitter, that the victims were Swedish.

“I have just offered my sincere condolences to the Swedish PM following tonight’s harrowing attack on Swedish citizens in Brussels,” de Croo wrote.

“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 federal prosecutor said the third victim, who was wounded but whose condition was not life-threatening, was a taxi driver. The prosecutor called on Brussels’s residents to stay indoors until the threat was over.

The threat alert in Brussels was raised to its top rating of 4, meaning a “threat is extremely serious”. It was previously at 2, indicating an average threat.

The suspected assailant, calling himself Abdesalem Al Guilani, claimed in a video on social media that he was “a fighter for [God]” and a member of ISIL (ISIS).

One Belgian newspaper said it was likely the victims were football supporters given that Belgium was hosting Sweden in a Euro 2024 qualifying match on Monday evening. The match in front of 35,000 fans was in the national stadium not far from the shooting and was suspended at half-time for security reasons.

Fans were told to remain in the venue after the suspension and were allowed to leave after a couple of hours.

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

Video footage of the attack shared on media outlets showed a man in an orange fluorescent vest arriving on a scooter, dropping the vehicle and immediately taking out a large weapon and opening fire on passersby.

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