Armed police officers stand guard following a blast at National Monument (Monas) complex in Jakarta, December 3, 2019. An explosion on Tuesday in Indonesia's National Monument park that injured two military personnel appeared to have been caused by a smoke grenade. REUTERS/Willy Kurniawan

Indonesian police officers stand guard following a blast at National Monument (Monas) complex in Jakarta, December 3, 2019. The two injured officers were doing exercises in the park at the time, Jakarta military chief Eko Margiyono added. REUTERS/Willy Kurniawan

Armed police officers stand guard following a blast at National Monument (Monas) complex in Jakarta, December 3, 2019. The park explosion was suspected to have been caused by a smoke grenade, and two injured military officials had been taken to hospital. REUTERS/Willy Kurniawan

An armed Indonesian police officer walks as he guards following a blast at National Monument (Monas) complex in Jakarta, December 3, 2019. REUTERS/Willy Kurniawan

An Indonesian forensic policeman takes pictures of evidence of a blast at National Monument (Monas) complex in Jakarta, December 3, 2019. REUTERS/Willy Kurniawan

Police tape cordon off an area following a blast at National Monument (Monas) complex in Jakarta, December 3, 2019. REUTERS/Willy Kurniawan