At least 54 people were injured on Friday after multiple explosions at a mosque within a school complex in Indonesia’s capital Jakarta, police said.

The victims, who were mostly students, sustained a range of injuries, local police chief Asep Edi Suheri said.

“Some have minor injuries, some moderate, and some have already been discharged,” Asep said.

A 17-year-old who was undergoing surgery in hospital has been identified as the “suspected perpetrator,” deputy house speaker Sufmi Dasco Ahmad told reporters.

A student at the school told state media agency Antara that the suspect was a fellow student who had been bullied and “wanted revenge.”

Listyo Sigit Prabowo confirmed that the suspect had attended the school, and that police were investigating his background and possible motive. He added that there were so far no fatalities from the explosions.

Armed police were at the sceneImage: Willy Kurniawan/REUTERS

What do we know about the Jakarta school explosions?

Witnesses told local television that two blasts were heard at around midday, during a sermon at the mosque at SMA 27, a state-funded high school located inside a navy compound.

Deputy coordinating minister of politics and security, Lodewijk Freidrich Paulus, said there had been two explosions at the back of the mosque and near its door.

“Don’t jump to the conclusion that this is a terrorist act,” Lodewijk said, according to Antara.

Police have not disclosed the cause of the incident, which occurred in the Kelapa Gading district of North Jakarta.

The area has been cordoned off with police officers “processing the crime scene,” police chief Asep said. He said a bomb squad had been deployed.

“We are still investigating, as this incident just occurred,” Asep said, urging the public not to speculate on the cause or potential motive.

“Let the authorities work first,” he said.

The explosions come weeks after a building at an Islamic boarding school collapsed, killing at least 60 people.

Edited by: Kieran Burke