SYDNEY — Five Australian teens were arrested Saturday on suspicion of plotting an Islamic State group-inspired terrorist attack at a ceremony that included targeting police officers, officials said.

The suspects included two 18-year-olds who are alleged to have been preparing an attack at the ANZAC Day ceremony in Melbourne later this month, Australian Federal Police Acting Deputy Commissioner Neil Gaughan said.

Another 18-year-old was arrested on weapons charges, and two other men, ages 18 and 19, were in custody and assisting police. All the arrests took place in Melbourne.

ANZAC Day is the annual April 25 commemoration of the 1915 Gallipoli landings – the first major military action fought by the Australian and New Zealand Army Corps during World War I.

Police said they believe the plot was inspired by the Islamic State group, also known as ISIS, and was to have involved “edged weapons.”

“At this stage, we have no information that it was a planned beheading. But there was reference to an attack on police,” Gaughan said. “Some evidence that we have collected at a couple of the scenes, and some other information we have, leads us to believe that this particular matter was ISIS-inspired.”

Australia’s government has raised the country’s terror warning level in response to the domestic threat posed by supporters of the Islamic State.