An 18-year-old man has been charged after allegedly making threats at the Sydney Opera House.
The backpack-carrying teenager was allegedly making extremist remarks when police officers and security at the Opera House forecourt approached him on Thursday morning.
His backpack was seized and is undergoing forensic examination, police said.
Officers from the NSW Police Terrorism Investigations Squad were brought in to investigate, and a search warrant was carried out at the man's home in Narwee, in Sydney's south, where a number of items were seized for examination.
Police said in a statement they "are reassuring the community there is no ongoing threat in relation to this incident.
"Anyone with information should always come forward no matter how small or insignificant you may think that may be."
The 18-year-old has been in police custody since he was arrested on Thursday.
He has now been charged with threatening to destroy or damage property, police said.
The man has been refused bail and is due to face Central Local Court on Friday.
The incident comes just days after the Islamic State group issued a directive to its "lone wolf" followers to stab, shoot, poison and run over Australians at iconic attractions including the Opera House.
"Kill them on the streets of Brunswick, Broadmeadows, Bankstown, and Bondi. Kill them at the MCG, the SCG, the Opera House, and even in their backyards," the first issue of the terrorist group's new online propaganda magazine said.
