Belgian police shot a suspected suicide bomber at Brussels Central Station after a small explosion was set off.
Police said there were no other casualties and the situation was under control. It was not immediately clear whether the person who was shot was still alive.
Belgian media reported the person who was wearing an explosive vest, but police could not confirm this.
Authorities were investigating whether it was a terrorist incident, a spokesman for the national Crisis Centre said.
Explosion-like noises were heard at the Brussels train station and the city's main square, the Grand Place, was evacuated, Belgian media reported.
The police spokesman said: "There was an accident at Central Station. There was an explosion around a person. That person was neutralised by the soldiers that were on the scene.
"At the moment, the police are in numbers at the station and everything is under control."