At least 55 people, most of whom are students, were left injured after multiple explosions rocked a mosque at a high school in Jakarta, Indonesia. The horrifying incident happened as Friday prayers were underway.

Witnesses told local television stations that they heard at least two loud blasts around noon local time (5am GMT) from inside and outside the mosque, just as the sermon had started inside SMA 72, a state high school within a navy compound in Jakarta’s northern Kelapa Gading neighbourhood. Students and others were also seen running outside the building in a panic, as grey smoke filled the mosque. 

Indonesian authorities have since said they have identified a 17-year-old boy as a suspect. 

Police have for now brushed away speculation that the blasts were a terror attack, saying they were still investigating. 

Deputy House Speaker Sufmi Dasco Ahmad told reporters after visiting student victims at a hospital: “The information I have is that the suspect is undergoing surgery. The suspect is a 17-year-old male student.”