Sydney - An Australian man was charged on Wednesday with possessing documents connected to a planned terrorist attack on government targets in Sydney as police insisted people should not be afraid.
Sulayman Khalid, aged 20, was arrested following raids last week which uncovered a large number of documents, a rifle, and two shotguns.
He was charged with being in "possession of documents designed to facilitate a terrorist attack", while a 21-year-old was accused of breaching a control order issued by a judge.
Their arrests come on the back of a series of pre-dawn raids across Sydney and Brisbane in September as concern mounts about the flow of people to Iraq and Syria to join the Islamic State of Iraq and Syria (ISIS) group and other jihadists.
Also Read:Memorial services held for Sydney siege victims
After that operation, police said they had foiled a plot to "commit violent acts" in Australia, including a plan to behead a member of the public.
More than 70 Australians are currently fighting for Islamic militants overseas. At least 20 have died and there are fears that increasing numbers of youths are being radicalised and could mount attacks at home.
"Certainly the documents talked a little bit about potential government targets," said Australian federal police deputy commissioner for national security Michael Phelan.
He said the targets were in Sydney, but did not go into detail.
"I am confident that we've disrupted the activity that they were planning. And that is all I'm prepared to say at this particular point."
Khalid was remanded in custody and will face court again in February. The second man has yet to appear in court.
The arrests follow warnings on Tuesday by Prime Minister Tony Abbott of heightened "terrorist chatter" in the aftermath of a fatal cafe siege in Sydney's financial hub last week.
Iranian-born gunman Man Haron Monis, who had a history of extremism and violence, took 17 hostages in the city's financial heartland, unveiling an Islamic flag.
He was killed as armed police stormed the eatery after 16 hours. Two hostages also died -- mother-of-three Katrina Dawson, 38, and 34-year-old Lindt cafe manager Tori Johnson -- while several were injured.
"A briefing from the security agencies today indicated that there has been a heightened level of terrorist chatter in the aftermath of the Martin Place siege," Abbott said Tuesday.
"That's why it's important that people remain alert and aware as well as reassured that our police and security agencies are doing everything they humanly can to keep us safe."
Ideology linked to IS
Australia has not officially branded the Sydney siege a terrorist attack and Abbott declined to speculate on any potential new threat.
Phelan said police had been monitoring a particular group of between 15 and 20 people with 11 of them charged since the September raids, some for "serious terrorism offences".
"It is a group of people here in Sydney that we've been actively monitoring for a long period of time now and any action they take we want to try to get ahead of them," he said.
Asked if they had a name, he replied: "No. Certainly their ideology is linked to ISIS overseas."
Also Read: Court orders partner of Sydney hostage-taker jailed
Phelan added that they had no direct link with Monis but "certainly since the tragic events of last week, this group had ongoing conversations and activity".
Australia raised its threat level to high in September, which means an attack is likely.
New South Wales police deputy commissioner Catherine Burn stressed people should not be afraid.
"This should not disrupt our way of life in any measure at all," she said.
"We're clearly vigilant and everybody should be vigilant. However, I think that the activity that we have undertaken has put us in a very, very good position."
Following the cafe siege, security across Sydney was stepped up with hundreds more officers on the streets.