"Owing to the explosion, nearly 60 percent of the building was damaged," Manager of the Center for Disaster Control Operation of the Medan City Disaster Mitigation Office Drs Nurly stated.
The cause of the explosion at the Fountain Restaurant is yet unknown.
"The authorized agency continues to investigate the cause of the explosion," he stated.
The police has cordoned off the building with police line.
In the meantime, an anti-bomb squad of the Mobile Brigade (Brimob) unit of the North Sumatra Provincial Police has been sent to the scene.