The Police in Sydney have arrested two male suspects in a counter-terror operation.

The 15-year-old and a 20-year-old have been charged with conspiracy to conduct a terrorist act.

The Police explained that the arrests were linked to a plot outlined in a material seized in 2014 as part of Operation Appleby.

The operation in September 2014 was sparked by intelligence reports that Islamist extremists were planning random killings in Australia.