Sydney; Martin place cafe with reports of at least 50 people have been taken hostage,it's unfolding now live on TV channel 7.Even footage of a guy wearing a headband with writing on it .Very scary considering several months ago this area was named as a terrorist attack but was foiled.
Islamic state flag now confirmed up in the cafe...
."Police operation is taking place in Martin Place Sydney Photo: Police with guns drawn outside a building in Martin Place in Sydney's CBD. (ABC News: Sarah Gerathy)
A number of hostages have been taken in a siege in Sydney's CBD.
At least three people can be seen through the windows of a cafe in Martin Place with their hands raised.
An Islamic flag has also been seen hanging in the window of the Lindt Chocolat Cafe.
Witnesses have reported hearing loud bangs that sounded like gun shots.
One block of Martin Place has been cordoned off between Elizabeth Street and Phillip Street.
Dozens of police cars are at the scene and one police officer has drawn his gun.
Police have urged members of the public to avoid the area.
The Channel Seven newsroom opposite the cafe has been evacuated.
Seven producer Patrick Byrne said staff at the network watched the situation unfold.
"We raced to the window and saw the shocking and chilling sight of people putting their hands up against the panes of glass at the cafe," he said.
"This was just extraordinary.
"Then, as we were looking wondering what was going on, it seemed to be like an armed hold-up, more police arrived at Martin Place.
"The area was cleared. People were kept back.
"It was then that gasps went through the newsroom as an ISIS flag was put up against one of the window panes."
More to come."