An explosion at a mosque in Indonesia's capital Jakarta during Friday prayers injured dozens of people, police said, without giving any early indication of the cause.
Jakarta city police chief Asep Edi Suheri told reporters 54 people had been admitted to hospitals with a range of minor to serious injuries, including burns from the blast at the mosque inside a school complex in the Kelapa Gading area.
An investigation was underway.
News channel KompasTV showed footage of a green-painted mosque with a line of shoes outside, cordoned off with police tape. There were no signs of damage to the exterior.
"We have taken several measures such as investigating the crime scene, setting up a police line and sterilising the area," Suheri said.
State news agency Antara quoted the deputy chief security minister Lodewijk Freidrich as saying there were two explosions at the mosque.
Black-clad police carrying assault rifles guarded the iron gates of the compound, with emergency vehicles and armoured police vehicles on the street outside, according to a Reuters journalist.
The complex is located in a crowded area of North Jakarta on largely navy-owned land, home to many military personnel and retired officers.
There was no indication if the explosion might have been an accident or an act of malice. Indonesia does have a history of attacks on churches and Western targets - but not mosques - and Islamist militancy has largely been suppressed in recent years.
