The Kuala Lumpur fire and rescue department said the explosion occurred in the air-conditioning compressor room located within the fourth-floor cafeteria while maintenance works were being carried out.

The blast caused about 30% structural damage to the fourth floor but did not result in a fire, it said in a statement.

Kuala Lumpur police chief Fadil Marsus said some of the victims were in critical condition after being injured by debris from the powerful blast, Berita Harian reported.

Fadil said the explosion is believed to have been caused by a gas leak from the air-conditioning compressor.

He said the air-conditioning system was being repaired by technicians at the time of the incident.

“Investigations so far have found no elements of criminal activity in this incident,” he said.

Of the nine injured, two were contractors, one was a member of the university’s management, two were foreign cafeteria workers, and four were students.

Fadil said there were not many students at the time as most of them were still on holiday.

He said the fire and rescue department’s hazardous materials (Hazmat) team was conducting an inspection.

“The area is safe, but a full inspection is being carried out to prevent any subsequent explosion,” he said.