TEHRAN  - A seven-storey building collapsed in northwest Tehran on Monday, leaving between three and 19 people dead, local media reported. There was confusion over the toll with the student news agency ISNA saying that three people had been confirmed killed in the collapse, while state radio gave the toll as high as 19. "Workers were sleeping in the building which collapsed in the morning," Tehran prosecutor Saeed Mortazavi was quoted as saying by state radio. "Unfortunately all these workers " about 20 " were affected by the accident. So far no-one has been rescued," he added.