Five people including two policemen were killed and at least 11 others injured during the collapse of several buildings in Iran's capital, local media reported on Monday.
The policemen were securing the planned demolition on Sunday of "unauthorised buildings" in Tehran's southwest, ISNA news agency said. Another news agency, Tasnim, said two of the officers were killed.
The overall "toll from the collapse" has reached five, spokesman for Tehran's fire department, Jalal Maleki, told Fars news agency.
According to ISNA, authorities had begun the demolition of one building when five others collapsed.
Rescue operations were underway to find others who may be trapped under the rubble, ISNA and Tasnim reported.
Photographs from the scene issued by Tasnim showed rescuers and heavy equipment working below a pile of debris and twisted metal several metres (yards) high, with other unfinished and partially damaged buildings around them.
ISNA quoted a police statement saying the buildings which collapsed did not comply "with construction safety measures".
A Tehran city official said on Saturday that authorities had demolished more than 46,000 unauthorised buildings over the past two years, according to Hamshahri newspaper.
In May 2022, a building collapse in Iran's southwest killed 43 people, in one the country's deadliest such incidents.
The collapse of the 10-storey Metropol building, which had been under construction in the city of Abadan in Khuzestan province, sparked protests across the country decrying corruption and incompetent authorities.