Dozens of people have been rushed to hospital after an explosion at a mosque in the Indonesian capital Jakarta, local police said.

The incident happened during Friday prayers inside a school complex in Kelapa Gading, North Jakarta.

City police chief Asep Edi Suheri said the cause of the explosion is still being investigated.

Fifty-four people have been admitted to hospital with injuries ranging from minor to serious and including burns, Suheri said.

Local news channels showed footage of a police line around the school with ambulances standing by. Images of the mosque showed no extensive damage.