Police have arrested a man on suspicion over his links with ISIS after he threatened the public outside the Sydney Opera House on Thursday morning.

He was arrested in the forecourt at around 11:20 am as bomb squad officers evacuated the popular public place. Police confirmed that the man is due to appear in a Sydney court on Friday and is likely to face imprisonment of five years if proven guilty.

The event has come following a recent warning issued by the Islamic State militants in their first-ever English language magazine, where they indicated that they are plotting on attacking several landmarks across Australia, including the Sydney Opera House and the Melbourne Cricket Ground.

In the publication “Rumiyah”, the extremist group asked its “lone wolf” followers in Australia to stab, shoot, poison and run over Australians at the mentioned places.

The appearance of the man just after the warning has made the matter even more serious. The NSW police detained the 18-year-old with a backpack on the basis of doubt. He was reportedly found making extremist comments when police went to arrest him. The law enforcement officers seized his backpack and sent it for forensic inspection.

A warrant was also issued following which the police visited the alleged man’s home at Narwee where they seized several items for further examination. The Terrorism Investigations Squad, according to reports, is investigating the matter.

Police, according to The Daily Mail, said that the same man was arrested in 2015 for making hoax threats and is believed to be suffering from “serious mental health issues.” The officers claimed that he was continuously in surveillance after the man indicated his strong desire to join the ISIS earlier.

The police have charged the man with threatening to destroy or damage property. The Sydney Morning Herald reported that the man was refused bail and is expected to remain in custody until he appears at Central Local Court on Friday.