Two men were arrested as part of an ongoing counterterrorism investigation into a group that officials have accused of plotting to kill a random member of the public in Sydney, police said Wednesday, one day after the nation’s prime minister warned of heightened terrorist chatter in the aftermath of a deadly siege in a Sydney cafe.

Sulayman Khalid, 20, was charged on Tuesday with possession of documents designed to facilitate a terrorist attack, while a 21-year-old was charged with breaching a control order, police said.

Australian Federal Police Deputy Commissioner Michael Phelan said there was no specific terrorist threat and the arrests were related to an ongoing counterterrorism operation that led to a series of raids in Sydney in September. One man was charged at that time with conspiring with an Islamic State leader in Syria to behead a random person in Sydney.

Tuesday’s arrests bring to 11 the number of people charged in connection with that operation.

“There is nothing that indicates at all that (there were) any specific targets or time frame in relation to this particular activity at all,” Phelan said, though he added that the documents seized by police did talk about potential government targets.

The latest arrests come one day after Australian Prime Minister Tony Abbott warned there had been a “heightened level of terror chatter” in the week since a gunman took 18 people hostage in a downtown Sydney cafe. The standoff ended 16 hours later when police stormed the cafe in a barrage of gunfire to free the captives. Two hostages were killed, along with the gunman, an Iranian-born, self-styled cleric.

Australia’s government raised the country’s terror warning level in September in response to the domestic threat posed by supporters of the Islamic State group.

The Sydney group that police have been investigating in relation to the alleged terror plot revealed in September involves about 15 to 20 people, and their ideology is linked to the Islamic State movement, Phelan said. They have also been accused of supporting terrorism by providing funds and facilitating the travel of people headed overseas to fight alongside extremists.

Police investigating the group issued additional search warrants last Thursday and seized a large number of documents and three guns from a home, New South Wales Deputy Police Commissioner Catherine Burn said.

The documents seized “talked a little bit about potential government targets” in Sydney, Phelan said. The material was concerning enough that police decided to move in and make the arrests, he said.

“I am confident that we’ve disrupted the activity that they were planning,” Phelan said.

Khalid made a brief appearance via video link at Parramatta Local Court in western Sydney. He did not apply for bail, and the matter was adjourned until Feb. 18. He could face up to 15 years in prison if convicted.

The 21-year-old, whose name has been suppressed by the court, was also denied bail. He is charged with breaching a control order, an offense that carries a maximum sentence of two years in prison.

Judges sometimes issue control orders against persons of interest in criminal cases, restricting them from engaging in certain activities. In court, prosecutors said the man had breached an order preventing him from accessing certain forms of telecommunication by making a call from a public pay phone and from an unapproved mobile phone.

The man’s lawyer, Arjun Chhabra, argued the breaches were “incredibly technical” and said there was no suggestion his client had been talking about anything nefarious. SAPA