SYDNEY (TIP): Counterterrorism raids in Sydney on Sept 17 were sparked by security intelligence that the Islamic State movement was planning a public killing as a demonstration of its reach, the prime minister said on Sept 16. Australian police detained 15 people on Thursday in a major counterterrorism operation, saying intelligence indicated a random, violent attack was being planned on Australian soil. Prime Minister Tony Abbott said he had been briefed on Wednesday night about the operation which had been prompted by information that an Islamic State movement leader in the Middle East was calling on Australian supporters to kill. “Quite direct exhortations were coming from an Australian who is apparently quite senior in ISIS to networks of support back in Australia to conduct demonstration killings here in this country,” Abbott told reporters, referring to the al-Qaida splinter group leading Sunni militants in Iraq, Islamic State of Iraq and the Levant, which now calls itself simply Islamic State.