A witness named Maryati was near the site of the explosion. She said the explosion was loud enough to make people panic.
"I had to close my ears," Maryati said.
The explosion occurred in the National Monument Park (Monas) opposite the Ministry of Home Affairs (Kemendagri). Two Indonesian Armed Force (TNI) members were injured in the incident.
"Two TNI members are being treated at the Central Army Hospital (RSPAD) Gatot Subroto," Metro Jaya Police Chief Inspector General Gatot Eddy Pramono said at Monas, Central Jakarta on Tuesday, 3 December 2019.
The two TNI members have been identified as Fajar Arisworo and Gunawan Yusuf. Gatot said one of the victims was injured in the right and left hand. Meanwhile, Gunawan was injured in the thigh.