Indonesian policemen examine debris from a bomb blast inside a Starbucks coffee at Thamrin business district in Jakarta, January 14, 2016. [Photo/Agencies]

"The Starbucks cafe windows are blown out. I see three dead people on the road. There has been a lull in the shooting but someone is on the roof of the building and police are aiming their guns at him," Reuters photographer Darren Whiteside said as the attack unfolded.

Police responded in force within minutes. Black armoured cars screeched to a halt in front of the Starbucks cafe and sniper teams were deployed around the neighbourhood as helicopters buzzed overhead.

Jakarta police chief Tito Karnavian said one man entered the Starbucks cafe and blew himself up, wounding several inside.

As people poured out of the cafe, two waiting gunmen opened fire on them. At the same time, two militants attacked a police traffic post nearby, using what he described as hand grenade-like bombs.

After the militants had been overcome, a body still lay on the street, a shoe nearby among the debris. The city centre's notoriously jammed roads were largely deserted.

Indonesia has seen attacks by Islamist militants before, but a coordinated assault by a team of suicide bombers and gunmen is unprecedented and had echoes of the sieges seen in Mumbai seven years ago and in Paris last November.

The last major militant attacks in Jakarta were in July 2009, with bombs at the JW Marriott and Ritz Carlton hotels.

But the country had been on edge for weeks over the threat posed by Islamist militants.

Counter-terrorism police had rounded up about 20 people with suspected links to Islamic State, whose battle lines in Syria and Iraq have included nationals from several Asian countries.