Several people were trapped in a high rise shopping complex in the Bangladeshi capital Dhaka on Friday after a fire broke out, police and witnesses said, according to Reuters. Thick smoke rose over the 21-storey building and flames could be seen on the upper floors, a witness said. Army helicopters were trying to rescue people from the rooftop of the building, the country's largest shopping mall. "The fire broke out on the top floor and soon engulfed the other floors," a fire brigade official said. Television pictures showed the blaze spreading through five or six top floors. Police said they did not have any information about casualties. "It is still on fire, and we don't know if anyone died or was injured," one police officer said. The cause of the fire was not known.