Nearly 80 people have been injured after a ceiling inside the Jakarta stock exchange tower collapsed.
CCTV footage showed a group of about 40 visiting students walking on the mezzanine floor before it suddenly crashed down.
People can be seen falling into the lobby below as the ceiling collapses with no apparent warning.
Workers fled the building through piles of debris strewn across the lobby outside a Starbucks coffee shop.
Paramedics treated the injured on the grass and pavement outside the tower.
National police spokesman Setyo Wasisto said most of the injured were college students visiting the stock exchange as part of a study tour from Palembang in Sumatra.
He ruled out terrorism as the cause.
“There is no bomb element in the incident,” he said.
Hundreds of students were in the building at the time, Jakarta police spokesman Argo Yuwono added.
“I saw many people bleeding”, student Rizki Noviandi, who was taking part in a competition at the building, told Metro TV.
“So many people were carried out of the building and were left on the grass outside until the ambulances arrived.”
One student said she felt a tremor just before the building collapsed. She said some of her friends were hit by debris and suffered head wounds and broken bones.
“Our search and rescue teams, the police, doctors, the firefighters are all still working,” Mr Wasisto said.
“They are cleaning the debris and also searching for other possible injuries.”
Five hospitals released figures showing 77 people were injured in the accident.
A spokeswoman for Jakarta’s Siloam Hospital said it received more than two dozen victims.
The stock exchange remained open for its afternoon trading session and its general manager, Tito Sulistio, said no one had been killed.
“I guarantee that there were no fatalities,” he said. “I helped evacuate the victims to the park and as far as I know, the worst injuries are fractures.”
He said the exchange will pay the students’ medical costs.
In 2000 Islamist militants bombed the Jakarta stock exchange, killing at least 10 people and injuring dozens.