A fire tore through a seven-storey office building in Indonesia's capital on Tuesday, killing at least 22 people, police said.

Police said a drone battery that exploded on the ground floor had likely ignited the fire, which spread to the upper levels of the building in central Jakarta before being put out.

"However, the exact cause is still under investigation by the forensic laboratory team," said Susatyo Purnomo Condro, the Central Jakarta police chief, telling reporters the force was "committed to thoroughly investigating this fire incident".

A witness told AFP that the fire broke out at lunchtime, and was already large by the time firefighters reached the scene.

"The door was closed. When the firefighters broke in, the fire was already big and very red," said Nurhayati, 53, who like many Indonesians only has one name.

Updating an initial toll of 17 killed, Susatyo said there were 22 victims including 15 women.

One of them was pregnant, he said.

The Jakarta Fire Department said at least 100 firefighters and 29 fire trucks were deployed to extinguish the blaze in Kemayoran, a busy area of the city centre.

A local police commander was injured while assisting the evacuation of the building, Susatyo said.

The police chief said firefighters were now focused on cooling the building and clearing thick smoke from several floors.

"We will search the place again once it is cleared," he said.

The police chief said most of the victims did not seem to suffer burns and most likely died of asphyxiation.

AFP footage showed the charred facade of the building, used by an agricultural drone services company, with some windows shattered.

Firefighters used large fans to cool down the site.

Curious onlookers watched the aftermath from afar as firefighters and police officers carried out a body bag from the burnt building.

Susatyo said police were "questioning all witnesses, including the business owner and the building owner".

The investigation will look into "whether the cause of the fire is linked to negligence or if there are other responsible parties", he added.

Deadly fires are not uncommon in Indonesia. In 2023, at least 12 people were killed in the country's east after an explosion at a nickel-processing plant.