Australian police have carried out major anti-terror raids triggered by a call from a senior Islamic State militant for "demonstration killings", Prime Minister Tony Abbott says.
The raids, involving at least 800 heavily-armed officers, took place in Brisbane and Sydney.
Fifteen people were arrested and one person has been charged with conspiracy to prepare a terrorist attack.
Police say the anti-terror operation was the largest in Australian history.
Tony Abbott this week announced he is sending 600 troops to the Middle East to assist in the fight against Islamic State.