Emir Balat, 18, and Ibrahim Kayumi, 19, entered their pleas during a court appearance on Wednesday, facing a sweeping indictment that includes conspiracy to support a foreign terrorist organisation and the use of a weapon of mass destruction.

Breaching Australian sanctions laws can result in penalties of up to 10 years’ jail and significant fines.

Attorney-General Pamela Bondi described the incident as an alleged ISIS-inspired terror attack that could have caused mass casualties.

Australia was one of the Western countries that produced the most young men per capita to fight for IS in the 2010s.

Prime Minister Anthony Albanese has used a visit to a specialist women’s health clinic in Melbourne’s west to champion what he described as the largest women’s health program ever delivered by a federal government.

One Nation leader Pauline Hanson called for a complete ban on their return, saying they “made their bed” by travelling to a war zone to support terrorists and have “no place in our society.”

The incident has triggered alarm after it emerged that Australian passports had already been issued to the group

Repeated international warnings that the direct or indirect cultivation of extremist networks — whether for global jihad or against neighbouring India or Afghanistan — would ultimately prove self-destructive for Pakistan are now playing out.

The National Day of Mourning in January will allow families further time to lay their loved ones to rest and for communities still recovering to come together in remembrance and resolve.

Tulsi Gabbard warned that the goal of Islamism was the “Islamisation” of countries around the world, adding that it was “probably too late for Europe — and maybe Australia”.