A police officer runs across Martin Place near Lindt cafe, where hostages are being held, in central Sydney December 15, 2014. Hostages were being held inside the central Sydney cafe where a black flag with white Arabic writing could be seen in the window, local television showed on Monday, raising fears of an attack linked to Islamic militants. (Photo by David Gray/Reuters)

Police officers are seen at a corner near Lindt cafe in Martin Place, where hostages are being held, in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

Police officers gesture near Lindt cafe in Martin Place, where hostages are being held, in central Sydney December 15, 2014. Dozens of hostages were trapped inside the central Sydney cafe on Monday, with local television showing some being forced to hold up a black flag with white Arabic writing in the window, raising fears of an attack linked to Islamic militants. (Photo by Jason Reed/Reuters)

Police officers position themselves at a corner near Lindt cafe in Martin Place, where hostages are being held, in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

A police officer runs across Martin Place near Lindt cafe, where hostages are being held, in central Sydney December 15, 2014. (Photo by David Gray/Reuters)

A police officer runs across Martin Place near Lindt Cafe where hostages are being held, in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

Reporters and other onlookers behind a police cordon are reflected in the glasses of a police officer near Lindt cafe in Martin Place, where hostages are being held, in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

Police secure the scene near Lindt Cafe, Martin Place on December 15, 2014 in Sydney, Australia. Major landmarks in Sydney, including the Sydeny Opera House, have been evacuated as police respond to a hostage situation inside a Martin Place cafe. (Photo by Don Arnold/Getty Images)

Armed policeman are seen outside Lindt Cafe on Philip St, Martin Place on December 15, 2014 in Sydney, Australia. Police attend a hostage situation at Lindt Cafe in Martin Place. (Photo by Mark Metcalfe/Getty Images)

Armed police stand at the ready close to a cafe under siege at Martin Place in Sydney, Australia, Monday, December 15, 2014. A gunman took an unknown number of people hostage inside a downtown Sydney chocolate shop and cafe at the height of Monday morning rush hour, with two people inside the cafe seen holding up a flag believed to contain an Islamic declaration of faith. (Photo by Rob Griffith/AP Photo)

A police officer runs across Martin Place near Lindt cafe, where hostages are being held, in central Sydney December 15, 2014. (Photo by David Gray/Reuters)

An armed police officer runs along the street close to a cafe under siege at Martin Place in the central business district of Sydney, Australia, Monday, December 15, 2014. A hostage situation erupted inside a chocolate shop and cafe in Australia's largest city on Monday, with the nation's prime minister saying it may be “politically motivated”. Television footage shot through the cafe's windows showed several people with their arms in the air and hands pressed against the glass, and two people holding up what appeared to be a black flag with white Arabic writing on it. (Photo by Rob Griffith/AP Photo)

People standing behind a police cordon look towards Lindt cafe in Martin Place, where hostages are being held, in central Sydney December 15, 2014. (Photo by David Gray/Reuters)

A woman is assisted as a group of people are evacuated by police from a building next to Lindt cafe in Martin Place, where hostages are being held, in central Sydney December 15, 2014. (Photo by David Gray/Reuters)

Ladies rush through Philip St past armed police at Lindt Cafe, Martin Place on December 15, 2014 in Sydney, Australia. Police attend a hostage situation at Lindt Cafe in Martin Place. (Photo by Mark Metcalfe/Getty Images)

People standing behind a police cordon look towards Lindt cafe in Martin Place, where hostages are being held, in central Sydney December 15, 2014. (Photo by David Gray/Reuters)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. Two more hostages have run out of the cafe at the center of a siege in Sydney, Australia's largest city, according to a Reuters witness at the site. The two women were both wearing aprons indicating they were staff at the Lindt cafe where a gunman has been holding an unknown number of hostages for several hours. Three men had earlier run out of the cafe. (Photo by Jason Reed/Reuters)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

An armed tactical response police officer grabs a hostage as she flees from a cafe under siege at Martin Place in the central business district of Sydney, Australia, Monday, December 15, 2014. New South Wales state police would not say what was happening inside the cafe or whether hostages were being held. But television footage shot through the cafe's windows showed several people with their arms in the air. (Photo by Rob Griffith/AP Photo)

A hostage runs to armed tactical response police officers for safety after she escaped from a cafe under siege at Martin Place in the central business district of Sydney, Australia, Monday, December 15, 2014. (Photo by Rob Griffith/AP Photo)

A hostage runs to armed tactical response police officers for safety after she escaped from a cafe under siege at Martin Place in the central business district of Sydney, Australia, Monday, December 15, 2014. (Photo by Rob Griffith/AP Photo)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

A hostage runs to armed tactical response police officers for safety after she escaped from a cafe under siege at Martin Place in the central business district of Sydney, Australia, Monday, December 15, 2014. (Photo by Rob Griffith/AP Photo)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

A hostage runs towards a police officer outside Lindt cafe, where other hostages are being held, in Martin Place in central Sydney December 15, 2014. (Photo by Jason Reed/Reuters)

A heavily armed police officer walks near Lindt cafe, where hostages are being held,in Martin Place in central Sydney December 15, 2014. Australian police locked down the centre of the country's biggest city on Monday after an armed assailant walked into a downtown Sydney cafe, took hostages and forced them to display an Islamic flag, igniting fears of a jihadist attack. Police said they knew of one armed assailant involved in the incident at the Lindt chocolate cafe in the heart of Sydney's financial district, but there could be more. (Photo by David Gray/Reuters)