SYDNEY, Oct. 12 (Xinhua) — Australian counter-terror authorities have arrested two 17-year-old males in the southwest of Sydney on Wednesday, pre-empting a terror attack.

"Two males were arrested in the southwest of Sydney relating to an ongoing investigation," a New South Wales state police spokesperson told Xinhua on Wednesday.

"Officers seized two knives and the pair remains in custody.

"Police are unable to release anything further at this time however there is no on-going threat in relation to this matter."

Local media reported the operation was related to an alleged new terror plot, not one before the courts, with the teenagers wielding bayonets when arrested.

It's believed at least one of the boys is known to police, having been previously questioned by federal authorities for failing to stand for Australia's national anthem while attending school, Australia's national broadcaster reported.

Australia, a staunch ally in the U.S led fight against terror in Syria and Iraq has remained on heightened alert for home-grown terror attacks for over two years, arresting or jailing at least 45 suspects in connection to domestic terror plots.

Authorities however are increasingly concerned about the young age of those being radicalized after a 16-year-old boy murdered police accountant Curtis Cheng in a lone-wolf style terror attack in early October 2015.

"In Australia and around the world, the age of people radicalized is getting younger, with online grooming tactics similar to those used by sexual predators," Australian Federal Police NSW state commander Chris Sheehan has previously said.

The two men and three others already in jail on related charges are believed to be associates, though no direct links, of those who radicalized the teenager.

In late February, the teenage bride of an Australian terrorism suspect was arrested by counter-terrorism authorities for allegedly possessing a knife, an Islamic State flag and documents relating to a terror attack. Her husband is already in custody on terror related charges.