Police snipers at an armed Siege at the Lindt cafe in the CBD with Staff being held at gunpoint. Picture: Richard Dobson. Source: News Corp Australia

When you are able to stand behind police tape in Martin Place, in the centre of Sydney, and watch a jihadist hostage siege unfold, you know that the War on Terror has arrived.

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Mostly, there was an unnerving calm across the place, broken now and then by police in dark ballistic armour, holding assault rifles, running to take shooting positions in the barren granite and concrete canyons.

It is true that no one yet knows the true motivations of the man who seized the small Lindt Café at around 9.45am AEDT, with a so-far undisclosed number of hostages.

However, the black flag his victims were forced to display in the window of the shop, bearing the inscription, “There is no god but Allah and Mohammad is his messenger”, says plenty.

Jihadist come in two types: those who are connected through wide networks and diligently scheme major attacks; and those who have no such connections but set themselves up as attention-seeking emissaries for a senseless cause.

So far, this man appears to fit the latter category but, whatever he is, what he has done is horrific.

How it was that three hostages came to be released at around 3.30pm, and then two more around 5pm, is not yet known.

Ongoing...The scene of a siege at the Lindt Cafe in Sydney's Martin Place. Picture: Supplied. Source: Twitter

But those that remained must have endured an unspeakable anguish, wondering whether one or all of them were to become gruesome trophies of the Islamic State.

ISIS has made known its intent to transport its rage from Syria and Iraq to the streets of Australia and relies heavily on choreographed ultra-violence to sell its message.

To a degree, it achieved that aim as a little cafe that symbolises nothing apart from a chocolate brand yesterday got the unwanted attention of the world.

The offices above the cafe house lawyers, not police, military or powerful multinationals that might be the basis of some political statement.

And that is the truly insidious nature of the threat: it is deliberately aimless. It promises only to harm ordinary people who cannot be expected to make provisions to defend themselves.

It was disturbing development when, yesterday midafternoon, NSW Police Commissioner Andrew Scippione revealed no contact had been made with the man four hours after he had taken over the cafe.

Working hard...Heavily armed police remain on the scene. Picture: News Corp/Adam Taylor Source: News Corp Australia

That changed as it was revealed police negotiators had finally made contact.

As the Prime Minister asked people to go about their usual business, things were far from usual in the business heart of Sydney’s CBD, where blocks were in shutdown as tactical police in heavy armour gear took position.

Some hid behind ballistic shields as they studied the doors of the cafe for movement.

And up to 200 citizens looked up from the south-side of the cafe, watching and waiting.

Rumours swept about. There was a bomb in the Sydney Opera House; someone had hijacked a train north of Hornsby; the man had left incendiary devices all over Sydney.

At one point, a man turned up and started yelling words to the effect of: “This is what happens when you let Muslims into Australia.”

Doing all they can...NSW Police Commissioner Andrew Scipione and NSW Premier Mike Baird address the media on the unfolding siege. Picture: News Corp Australia Source: News Corp Australia

The crowd rounded on him, telling him where to go, refusing to let all Muslims be associated with the actions of one man. He eventually did go, with the assistance of police.

It was a slightly positive moment in a dismal day for Sydney and Australia.

Carpenters and electricians left their building sites to come down and stare. Tourists gathered and office workers gaped up at the cafe in the near distance, to be witness to the extraordinary disruption.

But no one could say they never expected something like this would one day to happen.

One young bloke was on the phone to his mate, telling him: “Dude, it’s like the most interesting thing that’s happened in Sydney. Dude, you can literally drive straight through the action.”

At one point, a door on a building on the south side of the Lindt Café opened and some 20 or 30 office workers who’d been holed up were escorted to safety by police. Earlier, rescue police had escorted workers out of the offices over the Lindt Café down a ladder.

Mostly, it was watching and waiting, and hoping that negotiators could talk the man around. It appeared the siege was set to run long into the night.