Two people have been shot dead in the Belgian capital Brussels on Monday evening, police have said.
The Belgium-Sweden Euro 2024 qualifier football match being played in the city has been abandoned, Uefa said.
The gunman fled the scene and is still at large. Brussels has increased its terror threat to the highest level.
A spokesman for the Belgian federal prosecutor said another person had been wounded in the attack.
“Go home and stay at home as long as the threat has not been eradicated,” Eric van Duyse told Reuters, adding that the attacker claimed to be inspired by Islamic State.
A video posted on social media showed an Arabic-speaking man claiming he carried out the attack in the name of God.
The man in the clip said he had killed three people. The federal prosecutor’s office confirmed it has seen the footage but cannot say whether he is the gunman.
The video and others uploaded during the attack is being verified by police, the BBC has been told.
Federal prosecutors in Belgium have since said that a terrorism probe has been opened following the shooting on the Boulevard d’Ypres.
A social media video shared by newspaper Het Laatste Nieuws on Monday, but not verified by BBC News, showed a man wearing a fluorescent jacket get off a scooter armed with what appears to be an assault-style rifle before entering a nearby glass-fronted building.
He appears to then shoot at least one person.
The Swedish players told Uefa that they did not want to play the second half and the Belgium team agreed, according to Swedish broadcaster TV6.
Police and emergency services have cordoned off nearby roads following the shooting which happened at around 19:00 local time (17:00 GMT; 18:00 BST).
Belgian Prime Minister Alexander de Croo posted on X, formerly Twitter, that he had “offered my sincere condolences to the Swedish PM following tonight’s harrowing attack on Swedish citizens in Brussels”.
“Our thoughts are with the families and friends who lost their loved ones. As close partners the fight against terrorism is a joint one.”
It is not yet known whether the victims were in Brussels to watch their national team play.
French President Emmanuel Macron said that Brussels was again hit by an “Islamist terrorist attack”.
“Europe has been shaken,” he said, speaking in Albania.
European Commission President Ursula von der Leyen said her thoughts were “with the families of the two victims of the despicable attack in Brussels”.
“I extend my heartfelt support to the Belgian police, so they swiftly apprehend the suspect. Together, we stand united against terror,” she posted on X.