A mosque explosion injured dozens of worshippers at a school in Indonesia today.

The blast ripped through the building in Jakarta in the middle of Friday prayers.

Footage shows smoke billowing out of the mosque, located in a school complex in the Kelapa Gading district.

Students were evacuated as police cordoned off the area.

City Police Chief Asep Edi Suheri said at least 54 people, including schoolchildren, were rushed to hospitals for minor to serious injuries.

Budi Hermanto, spokesman for the Greater Jakarta Metropolitan Regional Police, said police were investigating the cause of the explosion, adding an 'object resembling an airsoft gun' was discovered at the scene.

He said: 'Basically, it looks similar, we can't be sure yet whether it's a firearm or a homemade weapon.'