By Raffi Berg BBC News
This video can not be played
The number of people killed when an unfinished building collapsed in south-west Iran has risen to 26, state media say.
Dozens more were injured when the 10-storey Metropol office block in Abadan crashed to the ground on Monday.
Pictures showed that concrete floors and steel beams had fallen on to the street below, crushing several cars.
A search and rescue operation is continuing, and the cause of the collapse is being investigated.
At least 10 people are reported to have been arrested, including the building contractor, the mayor and two former mayors.
Hundreds of angry people, many banging drums and hitting cymbals, took to the streets in Abadan on Thursday night and Friday morning, in protest.
Some shouted "death to incompetent officials" and hailed the "martyrs of Metropol", Iran's Fars news agency said.
شعار مردم #آبادان به مراسم #ورزشگاه_آزادی برای اجرای سرود #سلام_فرمانده : «تهران عروسیه - آبادان خون ریزیه» pic.twitter.com/LB7Jj0NVWG
State news agency Irna reported that the building was located on Abadan's busiest commercial street, and that its lower floors had been open for a few days while construction work continued above.
Witnesses said the collapse, which happened at around 12:40 local time (08:10 GMT), was sudden.
"I thought it was an earthquake at first," Ahmad, a shop owner, told the Associated Press.
The Iranian Red Crescent said 23 rescue teams from Abadan and neighbouring cities rushed to the scene along with more than a dozen ambulances.
Iran's Mehr news agency said most of those who were trapped had been shopping on the ground floor of one of the finished parts of the building.
The incident has raised questions about building safety standards in the country.
Top official Mohammad Mokhber told state TV he believed there had been "widespread corruption" during the construction of the tower.
According to local authorities, the building was only legally allowed to contain six floors, but four more were added when it was built, the Associated Press reported.
During the 1980s Iraq-Iran war, the region faced huge destruction - and many of the projects to rebuild the area were criticised for poor construction practices.
But still, the collapse in Abadan is the deadliest incident of its kind in Iran for years.
In 2017, at least 20 people were killed, including 16 firefighters, when the 17-storey Plasco building in Tehran caught fire and then collapsed.
How long can survivors last under rubble?
Rouhani vows action over quake collapses
Iran high-rise collapse kills 20 firemen
US Senate passes first gun control bill in decades
Trudeau denies meddling in mass shooting inquiry
Lawyers threatened to quit over Trump election pressure
Fury and questions over China's treatment of women
'They'd rather die than return to Nicaragua'
How big?! Weekly quiz: Which massive fish made the news?
Watch world's lowest parachute jump attempt. Video Watch world's lowest parachute jump attempt
The small port integral to Europe's energy future
What is India's 'luxury resort politics'?
Africa's top shots: Stretch, bend, dive
Sweden's 'blue hole' in the sky
The murder that sparked a civil rights movement. Video The murder that sparked a civil rights movement
Why top chefs are leaving Paris
"It started before Covid, but it was discreet"
The films bringing sex work to life
Has cinema perpetuated damaging stereotypes?
A growing and influential intellectual movement aims to understand why human progress happens – and how to speed it up
© 2022 BBC. The BBC is not responsible for the content of external sites. Read about our approach to external linking.