( CNN ) Two Sydney men have been charged with terror offenses , with one accused of possessing documents designed to facilitate a terror attack on Australian soil . Sulayman Khalid , 20 , from Regent 's Park in western Sydney , appeared in Parramatta Local Court Wednesday , after having been arrested at his home the previous day , police said . He was refused bail , and is scheduled to reappear in court on February 18 , court staff said . The maximum sentence he faces is 15 years , police said . A second man , a 21-year-old from the Sydney suburb of Marsfield , was also charged by counter-terrorism police with breaching a control order . A person can be subject to a control order if it substantially helps prevent a terrorist attack , or the person has trained with a listed terrorist organization or been convicted of terror offenses , according to the Australian Attorney General Department . The charge carries a maximum sentence of two years ' imprisonment . 'Overt action ' Australian Federal Police Deputy Commissioner Michael Phelan told reporters that the arrests related to `` activity that has been going for a while now . '' `` This group has had ongoing conversations and activity for the last year , '' he said , adding that `` particularly overt action '' had been taken on 18 September and again last week , prompting the authorities to obtain search warrants . A `` significant amount of material '' had been seized , he said . While there was no specific threat of an imminent attack , he told reporters : `` There was enough there that gave concern to us that something was being planned . '' `` The documents talked a little bit about potential government targets . '' 'Heightened ' threat . The arrests came the same day that Australian Prime Minister Tony Abbott warned of a `` heightened level of terror chatter '' following the Martin Place siege in Sydney , in which two people , along with hostage-taker Man Haron Monis , were killed . `` The terror threat remains high ... and at this level an attack is likely , '' Abbott told reporters Tuesday . `` We do n't know when and how an attack may come , but we do know that there are people with the intent and the capability to carry out further attacks . '' The arrests were made as part of Operation Appleby , an ongoing investigation into Islamist extremists , which led to sweeping pre-dawn counter-terror raids in Sydney in September . Eleven people have been arrested in relation to the operation so far , police said . Phelan said Operation Appleby was focused on a group of 15 to 20 people in the Sydney region who sympathized with ISIS ideology , and who had been actively monitored for some time . A police spokeswoman would not comment on claims in Australian media that the target allegedly mentioned in the documents was an Australian Federal Police building , or that the documents described a plan to conduct guerrilla warfare in New South Wales ' Blue Mountains . Following his arrest , footage appeared in Australian media of Khalid , dressed in a jacket bearing the ISIS flag , storming off the set of an Australian current affairs show in August in which guests had been discussing local support for Islamic extremism . READ MORE : Terror threats place Western nations on alert .
One Martin Place men have been charged as part of an ongoing counter-terror operation . Two is charged with possessing documents designed to facilitate a terror attack in Marsfield . He faces a maximum sentence of Tuesday .