Police in Brussels are searching for two gunmen after shots were fired outside a metro station, with authorities saying there was "no indication of a terrorist motive".
Locals officials instead linked the incident to the drug trade in the city which has spurred a rise in gun crime.
A police spokeswoman said shots were heard at around 6am (5am Irish time) outside a station close to the city centre.
Surveillance footage obtained by broadcaster RTBF showed two masked people carrying automatic rifles, with at least one letting off repeated shots.
"CCTV footage shows two people, at least one of whom is armed, the shots were fired into the air, there are no injuries," the police spokeswoman told AFP.
The suspects fled into the metro and entered tunnels under a main railway station, she added.
"A major search operation was launched," prosecutors said in a statement. "At this stage, there is no indication of a terrorist motive for this shooting."
Brussels transport authorities said three metro stations had reopened after police had initially ordered them closed.
Traffic on the network was resuming after the interruption.
Brussels has seen an increase in gun crime linked to disputes between rival drug gangs in the city.
Local media citing police figures say that there were 89 shooting incidents, killing nine people, in the city last year.
"No place for violence in Brussels and our big cities. This has gone on long enough!," said Belgium's Interior Minister Bernard Quintin, part of a new government sworn in this week.
"This government will apply zero tolerance to all forms of crime."
Quizzed by Belgian television at the scene, local mayor Fabrice Cumps said that it appeared "evident" that the shooting was linked to the drug trade.
"It reminds us of the need to mobilise fully to occupy the terrain and not give space to the traffickers," he said.
"It occupies my days and nights - we need to strengthen security for our residents."
Perched on the northwestern coast of the European mainland, Belgium has become a key hub for criminal gangs supplying narcotics across the continent.
The country has become a focal point for traffickers due to its giant Antwerp port that has served as a major smuggling gateway into Europe
