Reports say gunmen has taken about a-dozen hostages in a cafe on one of Sydney’s busiest streets.
Australia TV shows photos of staff and customers sobbing, as they are forced to stand with their hands pressed against the windows of the cafe.
A black flag with Arabic writing is also displayed.Hundreds of armed police have sealed off Martin Place in Sydney’s central business district.
Major landmarks in the city such as the Sydney Opera House have been evacuated.
Local media report that the airspace over Sydney’s central business district has been closed.
More information will follow.