|The Australian newspaper, which broke the story this morning, reported the plot centred on the Holsworthy Army base in western Sydney. Holsworthy is home to some of Australia's elite counter-terrorism troops.
The investigation of the group, dubbed Operation Neath, involved about 150 members of the Australian Federal Police, Victoria Police and ASIO. It was launched in late January after authorities intercepted a phone call from one suspect wanting help to fight in Somalia, according to The Australian.
The men arrested are Australian nationals of Somali and Lebanese background. Most are labourers employed in Melbourne's construction industry or taxi drivers. It has been reported that the alleged cell had about 18 members.
It was not immediately clear when the alleged attack was planned to have taken place. Victoria Police chief commissioner Simon Overland said more details would emerge when the men faced court.
But authorities believe the group was at an advanced stage of planning the alleged attack, which was conceived as punishment for Australia's military involvement in Muslim countries. NSW Police Commissioner Andrew Scipione said the attack was "likely imminent".
Electronic surveillance on the suspects is believed to have picked up discussions about ways to obtain weapons to carry out what would be the worst terror attack on Australian soil.
The alleged cell was inspired by the Somalia-based terrorist movement al-Shabaab, which is trying to overthrow the Somali government and replace it with an extreme brand of Islam. Two Melbourne men, both Somalis, have travelled to Somalia in recent months to obtain training with the extremist organisation, which is aligned with al-Qaeda, The Australian reported.
One of those men had already returned to Melbourne and is believed to have been among those arrested today. The other was still in Somalia.
Acting AFP Commissioner Negus said alleged members of the group had been seeking a fatwa to justify a terrorist attack in Australia.
It is understood that several members of the group wanted to travel to Somalia to fight with al-Shabaab, but when travel became difficult, they turned their attention to home.