Jakarta, Jan 16 (IANS): Over 70 people were injured on Monday when part of the first floor of in one of the two towers that house Indonesia's stock exchange building collapsed, police said.

The injured, many of them students visiting the building at lunchtime, were taken to four hospitals here, Jakarta police said in a statement, reported Efe news agency.

Jakarta police spokesperson Argo Yuwono, talking to the media outside the building, ruled out an explosion as a cause of the collapse.

The collapse occurred shortly after the conclusion of morning stock trading at 12.10 p.m. local time. Later, the country's stock exchange administrator ordered resumption of trading.

Most of the workers at the stock market returned for the afternoon session.

Images on television and social media uploaded by witnesses showed rubble in the lobby of the building.

The police cordoned off the area while an investigation into the incident is on.

National police spokesman Inspector General Setyo Wasisto said investigators would probe blueprint of the building after the incident, reported Xinhua.

"Every building has its own blueprint, so there must be information stipulating how long a building will remain strong," he said at the police headquarters, also adding the cause of the incident was not an explosion.

The country's financial services authority also supported the investigation, said head of its international division Anto Prabowo.