Men arrested over an alleged Christmas terror plot targeting Melbourne CBD landmarks appeared in court.
Four men have been charged with planning a terrorist act and remanded in custody.
A 21-year-old from Gladstone Park was released without charge.
Abdullah Chaarani, 26, of Dallas, was the first brought to the dock at the Melbourne Magistrates Court, shackled and with his hands cuffed before him.
Police documents filed with the court allege that between December 1 and December 22, Mr Chaarani "did engage in acts done in preparation for or planning a terrorist act".
Wearing a black Adidas t-shirt and sporting a long beard, Mr Chaarani was calm during his brief court appearance before Magistrate Mary Robertson.
Police will be required to present their evidence to Mr Chaarani's legal team by March 17.
The court was told he had been arrested as part of six raids held across Melbourne and, due to the complexity of the case, it would take police weeks to sift through the evidence collected at the properties.
Hamza Abbas, 21, of Flemington, later appeared in court wearing a grey t-shirt, and with a long beard. He was supported in court by four women.
Lawyer Jessie Smith, acting for the men, told the court Mr Abbas was vulnerable in custody because of his age, and the nature of the charges levelled against him.
"He does have some soft tissue damage from the arrest to his face, and I ask that he be tended to by a nurse," Ms Smith said.
She said Mr Abbas also had injuries to his back, hip and shoulder sustained in his arrest.
Ahmed Mohamed, a 24-year-old from Meadow Heights, was the third to appear in court.
Mr Mohamed smiled at the women in court and one, wearing a niqab, began to cry and was supported by the other women.
Ms Smith said Mr Mohamed had a pre-existing back injury and required prescription medication for his injury.
All three men were remanded in custody without applying for bail and were scheduled to face court again on April 28.
A fourth man, a 22-year-old from Broadmeadows, faced an out-of-sessions hearing on Friday evening.
He was remanded to appear at the Melbourne Magistrates' Court on Saturday morning.
Another of those arrested was Zakaria Dabboussi, an IT worker from Gladstone Park. He was later released without charge.
There were seven arrested in total after police stopped what police chief commissioner Graham Ashton said was a potential multi-mode attack at Federation Square, Flinders Street Station and St Paul's Cathedral.
A 20-year-old woman and a 26-year-old man, both from Meadow Heights, were released without charge.
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Mr Ashton earlier said the attack, using "explosive devices" was "mostly likely" set to be carried out on Christmas Day.
Apart from explosives, police also suspect guns and knives may have been used. Police said the suspects were "self-radicalised" but inspired by Islamic State.
Turnbull: Substantial terror plot
Prime Minister Malcolm Turnbull said the planned attack was "one of the most substantial terrorist plots that have been disrupted in recent years".
In strong words condemning the plot, Mr Turnbull said: "What these criminals seek to do is kill us but they also seek to frighten us, to get us to abandon our Australian way of life.
"They want to divide Australians. We will not let them succeed.
"I want to thank the men and women of the police in Victoria, the Australian Federal Police and ASIO and other agencies for their work in thwarting this terrorist activity, which was an Islamist terrorist plot inspired - as the Victorian police commissioner just observed a moment ago - by Daesh or ISIL," Mr Turnbull said in a press conference.
He outlined that 12 major plots had now been disrupted since September 2014, when the terror threat level was raised to "probable", and 57 people charged as a result of 25 counter-terrorism operations.
The level of threat remains the same.
"This news will be of great concern to all Australians. We are approaching the Christmas season, a time when we come together in peace and love, with our families. We congregate in public places for Christmas, for New Year's Eve. It is a time of happiness and joy.
"These terrorists sought to disrupt it. They have been thwarted. They are in custody. They are no longer a threat to Australians' security."
Homes raided in Melbourne's north west
Police said these men were Australian-born and in their 20s - except for one Egyptian-born man. Police said some had a Lebanese background.
Chief Commissioner Ashton said police executed search warrants in Flemington, Meadow Heights, Dallas, Campbellfield and Gladstone Park overnight as part of Operation Kastleholm.
The counter-terrorism operation also involved Australian Federal Police and ASIO.
"These individuals have been persons of interest for some period of time," he said. "They're people we have been concerned about for a period of time."
He said intelligence led police to step-up their investigation in the past fortnight. Surveillance of the suspects conducting reconnaissance at Federation Square lead them to believe the area was the intended target.
"If this had gone under guard, this would have been a significant attack," Mr Ashton said.
Mr Ashton said the raids had neutralised any terrorist threat to the city on Christmas Day.
The raid found evidence an improvised explosive device was being constructed.
"The attack had the potential to cause significant community harm," Mr Ashton said.
"The community should be concerned but should be reassured that we have got on top of this particular issue.
"The sort of threats that were presented really try to want us to cower before terrorism, but this is a clear example of where we don't cower before terrorism. We get on, we get out and enjoy Christmas, enjoy our new year."
'Separate the Muslim from terrorism'
In an old housing estate in Meadow Heights, police have cordoned off a small cul-de-sac where investigators carried out a raid on Thursday evening.
It's understood the raid took place in a converted garage attached to a home at the end of Manna Court.
A neighbour, who declined to be named, said he noticed police cars descend on the area at about 10pm on Thursday.
The working-class suburb north of Melbourne is home to a number of refugee families and the neighbour said he was annoyed that the alleged plot would shed Muslims in a bad light.
"So if we could separate the Muslim from the terrorism that would be great, " he said.
"In the past we have been called wogs and then that phased out. Then terrorism has brought the racism back.
"We just need to be vigilant and peaceful. We should all help each other out and get these thugs out."
Claims of excessive force
The Forum on Australia's Islamic Relations has released a statement alleging "excessive force" and "intimidation" was used by police conducting the raids.
"It's the same every time, there is an alleged plot and the raids are conducted in such a manner that the families are victimised and traumatised," said FAIR executive director Kuranda Seyit.
"The police will refer this to the Professional Standards Review Committee and we will never hear anything more about the impact that these raids have on the women and children who live in the homes of these alleged offenders.
"We condemn any act or preparation of an act of violence, however, our organisation's role is to keep Australia fair and to maintain a balanced and sensible approach to fighting terrorism, without trampling on our human rights or sacrificing our civil liberties in the process."
It is understood Islamic leaders were being briefed by police on Friday.
Islamic Friendship Association of Australia treasurer Keysar Trad said it was disappointing a few people were hearing a message that had "nothing to do with being a Muslim".
"Our religion is meant to promote the security and safety of everybody," Mr Trad said.
"We have to be thankful for the authorities that have been able to act quickly and, while we don't know the full details of the matter, I would much rather they err on the side of caution."
Islamic Council of Victoria President Mohamed Mohideen said: "We condemn any form of attack."
St Paul's Cathedral unshaken
St Paul's Cathedral featured in an Islamic State propaganda video released last month.
The footage, released on November 7, contained confronting images of beheadings, corpses and missiles in the Middle East, before a shot of Melbourne's cityscape appears.
The scene is followed by a blast at a mosque and then images of Melbourne Airport and St Paul's, on the corner of Flinders and Swanston streets in the CBD.
Melbourne was the only Australian city to feature in the 20-minute video, titled The Impenetrable Fortress.
Services will proceed at St Paul's Cathedral as planned over Christmas.
Very Reverend Dr Andreas Loewe, the Anglican Dean of Melbourne and St Paul's, urged Victorians tempted to point fingers to instead think of peace.
"St Paul's is one of Melbourne's most iconic religious buildings, a symbol of faith in our city and we work very hard to promote a degree of reconciliation between different faith communities in our city," Dr Loewe said.
"I believe this may well cast fears in peoples' hearts and minds and may well also point the finger at particular groups and I would want to encourage the people of Melbourne to enjoy their Christmas celebrations and to promote the values that Christmas stands for.
"I would encourage people to celebrate Christmas wholeheartedly, confidently and with great joy and particularly at this time giving thanks for our police and those working tirelessly to keep us safe."
Police numbers bolstered at events
Extra police will be at major events in coming weeks including the Boxing Day test and Carols by Candlelight.
Premier Daniel Andrews said the work of authorities had stopped a very serious matter and that there would be increased police presence at large gatherings.
"These threats are not notional they are very real right across our city and our state," Mr Andrews said.
"Victorians should go about their business; this is a very special time of the year."
In an environment in which "we cannot mitigate all risk," the Prime Minister also called on people to keep their eyes open and "speak up" if they see or hear anything suspicious, urging them to report it to the national security hotline.
Opposition Leader Bill Shorten said the arrests were concerning but echoed calls for Australians to enjoy the Christmas season as they normally would.
"The few extremists in our community who would wish to disrupt the Australian way of life, they win when we give up."
Federation Square venue managers shocked
Federation Square venue managers have said they were shocked to learn the tourist hotspot was a target.
Beer Deluxe venue manager James Curran said he felt "distressed" when he first heard the news. "Especially that it was planned for Christmas," he said.
Mr Curran said he was expecting the day's trade to be quieter than usual as many CBD businesses had closed for the year. He said no one had called to cancel bookings.
Elizabeth Velevski, manager of Federation Square restaurant Arintji, said she was "worried and concerned". "Everyone is living on the edge at the moment," she said.
A staff member from Taxi Restaurant said staff arrived at work in shock.
Most Federation Square restaurants, businesses and galleries will be closed on Christmas Day. Those which will trade are Mama's Gozleme, Melbourne Day Tours, which will close early, and Taxi, which will open for lunch.
- With Alexandra Laskie, Tom Cowie, Aisha Dow, Fergus Hunter