JAKARTA: Indonesian investigators were sifting through the rubble at Jakarta's stock exchange complex Tuesday as they looked for clues on what caused a walkway collapse that left scores injured, including dozens of students.

A mezzanine floor at the tower in the sprawling city's business district collapsed shortly before lunchtime Monday, injuring a total of 73 people, police said, adding that there were no deaths.

Dramatic CCTV footage showed a group of about 40 visiting students on a balcony section plunge as the floor gave way with a cascade of glass, metal and other material crashing onto the ground floor where several others were walking.

National police spokesman Setyo Wasisto said the investigation team is hoping to gather crucial evidence by the end of Tuesday, though the results of the probe will not be known for several weeks.

Officials have described the collapse as an accident and not the result of an explosion -- the tower was bombed by Islamist militants in 2000.

"If they (investigators) are done today, everything can be cleaned up and the...scene can be re-opened," Wasisto told AFP.

"Some tenants are a bit cautious even though building management said it's safe. They are also going to check the other mezzanine floor today."

Most of the injuries were broken bones, Wasisto said, adding that none were life-threatening.

A dozen people have so far been released from the hospital.

The damaged area remained closed off Tuesday but trading carried on as usual.

After the accident, which took place in one of the two towers in the stock exchange complex, the lobby was filled with debris and toppled-over plants near a Starbucks coffee outlet. The tower was built in the mid-nineties.

Hundreds of panicked employees were evacuated from the building, which also houses the local office of the World Bank.

"I would like to reiterate, it was an accident. It has nothing to do with a bomb or terrorism," Wasisto said.

At least 10 people were killed and dozens injured by a car bomb in the 2000 attack.

Some 200 cars were also damaged in the blast which happened in an underground parking lot. —AFP