At least two people are reported to have been killed in a series of blasts in the Indonesian capital, Jakarta, with gunfire breaking out afterwards.

The blasts happened outside the Sarinah shopping centre, near the presidential palace and UN offices, say reports.

A UN official near the scene, Jeremy Douglas, told the BBC that gunfire was ongoing.

Police have said they believe this is a bomb attack. There is no indication yet of who might be behind the assault.

Indonesia has been attacked by Islamist militant groups in the past and has been on high alert.

The area around the blast site has been cordoned off.

National police spokesman told AFP people had been warned to stay indoors in case of further explosions.

Mr Douglas said he had been about 150m away from one of the blasts.

"Then we ran into the building. We heard a third explosion. We got up to our office on the tenth floor and we heard a fourth, a fifth and a sixth.

"There is gunfire going on in the street right now."