Australian police have arrested four men in their twenties and a 15-year-old boy in Sydney over a suspected terror plot.

The arrests were made by the Joint Counter Terrorism Team (JCTT) Sydney as part of the ongoing Operation Appleby investigation into the alleged planning of a terrorist attack in Australia.

Each of the suspects has been charged with conspiracy to conduct an act in preparation for a terrorist act, with each alleged to have been involved in “formulating documents connected with preparations to facilitate, assist or engage a person to undertake a terrorist act”, say Australian Federal Police.

The charges are a result of information gleaned from material seized in December 2014 as part of Operation Appleby.

Australian Federal Police Deputy Commissioner National Security Michael Phelan said:

“The charges laid today are the direct result of ongoing investigations from material seized in previous Operation Appleby activity in Sydney during September and December 2014.

“The JCTT conducted disruption activity to ensure the safety of the community last year, and has continued to examine the evidence gathered and investigate potential criminal offences. We will allege that the charges today relate to evidence of a criminal act.”

New South Wales Police Deputy Commissioner Special Operations Catherine Burn added:

“It is disturbing that we continue to deal with teenaged children in this environment. To be putting a 15-year-old before the courts on very serious charges that carry a maximum penalty of life imprisonment demonstrates the difficulties law enforcement face.

“Operation Appleby has demonstrated the effectiveness of Joint Counter Terrorism Team’s efforts in NSW. I thank our officers for their dedication to the tasks of both disrupting terror planning and putting people before the courts when we have the evidence to do so.”

All face potential life sentences if convicted.