Jakarta, Nov. 7 -- The Indonesian Navy (TNI AL) and National Police (Polri) launched a joint investigation Friday after an explosion occurred at State High School 72 (SMAN 72) inside a navy housing complex in North Jakarta's Kelapa Gading Subdistrict.

Navy spokesman Rear Admiral Tunggul said authorities are still determining the cause and sequence of the blast, which occurred around 12:15 p.m. local time.

"The Navy and police are conducting an investigation to uncover the cause of the explosion," Tunggul said in a statement.

"Further information will be shared once verified data is available," he added.

He confirmed that several victims were taken by navy personnel to nearby hospitals for medical treatment but said the total number of...