A series of bomb blasts have rocked the Indonesian capital, Jakarta, followed by reports of continuing gunfire and at least three people killed.
Blasts hit several locations, including a cafe at a shopping centre near the presidential palace and UN offices.
There are reports of police snipers on the streets - a BBC reporter near the shopping centre said police have cordoned off the area.
There is no indication yet of who might be behind the assault.
Indonesia - the world's most populous Muslim country - has been attacked by Islamist militant groups in the past. It has recently been on high alert after threats from the so-called Islamic State.
'Gunfire right now'
National police spokesman told AFP people had been warned to stay indoors in case of further explosions.
A UN official, Jeremy Douglas, told the BBC had been about 150m away from one of the blasts near the UN building.
"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."
A Reuters photographer said one explosion had been at a Starbucks cafe, with its windows blown out.
He said police appeared to be aiming guns at a man on the roof of the building.