Three people were killed and at least 17 injured in a massive explosion at an apartment building in the Belgian capital Brussels, dpa quoted police as saying Sunday. One of the injured was in a critical condition. The blast, believed to have been caused by a gas leak, occurred shortly before midnight Saturday (2200 GMT) in the eastern municipality of Schaerbeek. Rescue workers found the bodies of three men, two aged 58 and one 66, in the rubble. The buildings on either side of the gutted apartment were damaged by the blast, which left behind a gigantic pile of stone, bricks, furniture and clothes. Neighbouring buildings were left with doors leading into the abyss. A wall clock and a washing machine faced into the open, the rooms they were once housed in blown away. The explosion shattered windows, split open doors and blew away roof tiles from many buildings in the area. Debris buried a ground- floor grocery store and a car parked in the street. Witnesses spoke of a bang comparable to a bomb explosion or an earthquake. "We thought it was an earthquake, the blast was so strong," one resident told local radio. A woman in the second floor of a destroyed house reportedly called for help as she stood on a piece of what once was a wall, holding on for dear life. "We couldn't help her because she was up too high," Adif, 49, said. "We had to wait until the firefighters came." As a precaution, several residents had to leave their homes to overnight elsewhere after the blast. In January, 14 people had been killed when a similar explosion caused a five-storey apartment building in the eastern town of Liege to collapse. About 20 residents were injured.