Six people were found dead inside a lift shaft at a building under construction in central Brussels on Tuesday after a fire broke out at the site, according to local authorities.

The victims were discovered inside a lift that had become trapped in the shaft at the Oxy tower, where firefighters carried out an operation lasting several hours to recover the bodies.

The fire broke out at around 08:00 local time and was brought under control shortly afterwards, but emergency crews found that flames had spread to the lift shafts where two lifts were stuck.

Officials had earlier said that at least six people were missing, with rescuers discovering several victims after forcing open one of the lifts.

“It could be the six missing people, but there could also be more in the other lift, or elsewhere,” Brecht Speybrouck, spokesperson for the Brussels Labour Prosecutor’s Office, said during the rescue operation.

The prosecutor’s office later confirmed that six bodies had been recovered from one lift.

Brussels Mayor Philippe Close thanked emergency services, saying they had carried out “an exceptional job” in “particularly difficult circumstances”.

Two people were taken to hospital with serious burns, according to local reports, while a firefighter received treatment at the scene after exposure to high temperatures.

Belgian Prime Minister Bart De Wever and King Philippe of Belgium visited the site during the afternoon.

The cause of the fire remains under investigation.

The Oxy tower, located around 500 metres from Brussels’ Grand Place, is currently under construction and is planned to include residential apartments, a hotel, restaurants and bars.