The 34-year-old manager of the Lindt Chocolat Cafe, Tori Johnson was shot while trying to grab the gunman's weapon, sources told Australian media.

Katrina Dawson has been confirmed as one of the two victims killed in the Lindt Chocolate Cafe siege in Sydney. She is a barrister and mother of two daughters and a son. Her youngest daughter is aged 4.

Killed suspect: Self-appointed Sheikh Man Haron Monis, the extremist Iranian-born gunman with a criminal history.

Australian security forces opened fire on Tuesday as they stormed the Sydney cafe where several hostages were being held at gunpoint

Police rescue personnel carry an injured woman from the Lindt cafe, where hostages are being held, at Martin Place in central Sydney December 16, 2014.

Hostages run towards a police officer (R) near Lindt Cafe, at Martin Place in central Sydney December 16, 2014.

Self-appointed Sheikh Man Haron Monis, the extremist Iranian-born gunman with a criminal history.

Two heavily armed police officers assist a hostage away from Lindt Cafe in Martin Place in central Sydney December 16, 2014.

A heavily armed policeman holds his weapon as paramedics rush towards the Lindt cafe, where hostages are being held, at Martin Place in central Sydney December 16, 2014.

A hostage (L) runs towards police officers near Lindt Cafe, at Martin Place in central Sydney December 16, 2014.

Hostages run past a police officer (C) near Lindt Cafe in Martin Place in central Sydney December 16, 2014.

This screengrab taken from Australian Channel Seven shows the suspected gunman inside a cafe in the central business district of Sydney on December 15, 2014. A gunman was holding terrified hostages inside a Sydney cafe December 15 with an Islamic flag displayed at the window, triggering a lockdown in an area home to government and corporate headquarters

Screengrab from TV broadcast shows presumed hostages holding up a flag with Arabic writing.

A hostage runs out of the cafe.

Two hostages (Lt) run for cover behind a policeman.

Two men run out of the Lindt cafe.

Two hostages (far left and far right) escape from the Lindt cafe during a siege by a gunman.

Two hostages (L) run for cover during a siege of the Lindt cafe.

A black flag with Arabic writing is held up at the window of the Lindt cafe.

A hostage runs out of the cafe.

A hostage runs out of the cafe.

A hostage escapes from the Lindt cafe.

A hostage escapes from the Lindt cafe.

Hostages were being held inside a central Sydney cafe where a black flag with white Arabic writing could be seen in the window.

Hands are pressed up against the window of the Lindt cafe where hostages are being held.

Hands are press up against the window of the Lindt cafe where hostages are being held.

Local television showed scenes of the siege in Sydney on Monday, raising fears of an attack linked to Islamic militants.

Australia is backing the United States and its escalating action against Islamic State in Syria and Iraq.

Prime Minister Tony Abbott said he was convening a meeting of the cabinet's national security committee.

He called it a hostage situation in Australia's commercial capital.

Australia's backing for the US means it is on high alert for attacks by radicalised Muslims or by home-grown fighters returning from the conflict in the Middle East.

Dozens of heavily armed police surrounded the Lindt Cafe in Martin Place.

Martin Place in central Sydney is home to the Reserve Bank of Australia, commercial banks and close to the New South Wales (NSW) state parliament.

Live television footage showed patrons inside the cafe standing with their hands pressed against the windows.

A black and white flag similar to those used by Islamic State militants in Iraq and Syria was also visible.

NSW Police tweeted: "A police operation is underway in Martin Place, Sydney's CBD. People are advised to avoid the area."

A couple of hundred people were being held back by cordons and the fire brigade's hazardous unit was on the scene.

The Reserve Bank of Australia, near the cafe, said staff had been locked down inside the building, and were all safe and accounted for.

Local media reported that the nearby Sydney Opera House had been evacuated after a suspicious package had been found.

Trains and buses were stopped and roads were blocked in the area, with train operators saying there had been a bomb threat at Martin Place.

In September, Australian anti-terrorism police said they had thwarted an imminent threat to behead a random member of the public.

A woman is assisted as a group of people are evacuated by police from a building next to Lindt cafe.

Police officers gesture near Lindt cafe in Martin Place, where hostages are being held.

People standing behind a police cordon look towards Lindt cafe in Martin Place.

Police officers position themselves at a corner near Lindt cafe in Martin Place.

People standing behind a police cordon look towards Lindt cafe in Martin Place.

New South Wales state police officers are seen at a corner near Lindt cafe in Martin Place.

Police officers are seen at a corner near Lindt cafe in Martin Place.

Police officers walk near Lindt cafe in Martin Place, where hostages are being held.

The police evacuate employees from the offices next to a cafe where hostages are being held.

A hostage is being taken to safety.

A floral tribute to the victims.

An injured hostage is being rushed to hospital.

Women comfort one another.

A floral tribute to the victims.

An injured hostage is being rushed to hospital.

Australians from all walks of life mourn victims of the cafe siege.

Muslims praying at the scene of the dramatic siege.

Australians from all walks of life mourn victims of the cafe siege.

A sad and tragic event that darkens the festive spirit as Australians prepare for Christmas.

Australians from all walks of life mourn victims of the cafe siege.

Floral tributes to the victims of the cafe siege.

A sad and tragic event that darkens the festive spirit as Australians prepare for Christmas.

Australians from all walks of life mourn victims of the cafe siege.