Iran's oldest high-rise in southern Tehran collapsed on Thursday morning following a major fire in the building, leaving dozens of people injured.
The 17-story structure crumbled after the fire engulfed the top floors of the building in downtown Tehran as scores of firefighters battled the blaze.
The Fars news agency and the IRIB news website said at least 30 firefighters were feared to have been killed in the incident but officials did not confirm any deaths.
The head of Tehran's emergency services told IRIB that at least 70 people have been injured and 23 hospitalized.
Tehran Mayor Mohammad Baqer Qalibaf said between 20 to 25 people are believed to have been trapped under the rubble.
Fars said a firefighter had texted a message to a colleague, saying he was alive and trapped with several others at the building's engine room.
Officials have not given the exact number of casualties so far.
Firefighters battled the blaze for several hours before the collapse as police kept out shopkeepers and others trying to rush back in to collect their valuables.
Iranian President Hassan Rouhani has ordered an immediate investigation into the causes of the tragedy.
Vice President Es’haq Jahangiri and Health Minister Hassan Ghazizadeh Hashemi also visited the site.
“The administration stands by the nation, and all relevant bodies have been mobilized to save the injured,” Jahanigiri told reporters.
Ghazizadeh Hashemi also said all hospitals and medical emergency centers in the capital are on high alert and fully prepared to provide aid to those wounded in the blaze and the ensuing building collapse.
The building came down in a matter of seconds, shown live on state television, which had begun an interview with a journalist at the scene.
A side of the building buckled first, tumbling close to a firefighter perched on a ladder and spraying water on the blaze.
Nearby buildings including the embassies of Turkey, Germany and the UK have been evacuated. Authorities at Tehran's governor's office have ruled out terrorism.
The tower was inaugurated in 1962 and named after a plastics manufacturing company. It was the tallest building in the city at the time of its construction. It included shopping centers and clothing workshops.
