A MEZZANINE has collapsed at the Jakarta Stock Exchange tower, injuring nearly 80 people and forcing a chaotic evacuation.

Security camera footage circulating online showed the collapse, with a group of people plunging several feet to the ground as the structure gave way beneath them.

People fled the building through a lobby strewn with debris, while emergency service personnel tended to the 77 injured people on the grass and pavement outside the tower.

The victims were described as having mostly suffered leg and arm injuries.

The lobby was crowded at the time of the collapse, just after people had finished lunch.

Police said the injured people are being treated in three different hospitals in Jakarta, but there have been no fatalities.

National police spokesman Setyo Wasisto said most of the injured were college accountancy students from Palembang in the island of Sumatra, who were visiting the Jakarta stock exchange as part of a study tour.

Wasisto ruled out terrorism as a cause of the collapse.

He said: “There is no bomb element in the incident.”

A student from Palembang said she felt a tremor just before the floor collapsed.

“The structure suddenly collapsed, causing chaos,” the student, identified as Ade, told MetroTV.

She said some of her friends were hit by debris and suffered head wounds and broken bones.

The area was evacuated and cordoned off by police but 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.

The stock exchange is a grand two-tower building with a large marble floor lobby. The Indonesian government has been pushing for more foreign investment.