A teenager pleaded guilty Thursday to plotting to run over and behead a police officer as part of an Islamic State group-inspired attack on an Australian Veterans' Day ceremony.

Sevdet Besim, 19, pleaded guilty in Victoria state's Supreme Court to one count of planning for a terrorist act, which carries a maximum sentence of life in prison.

Prosecutors said Besim was involved in a plot to attack last year's services in Melbourne or the neighboring city of Dandenong marking ANZAC Day, the annual commemoration of the 1915 Gallipoli landings in Turkey. The campaign was the first major military action fought by the Australian and New Zealand Army Corps during World War I and hundreds of thousands of people attend commemoration services around Australia.

In court documents, prosecutors said that Besim and a British accomplice had also discussed packing a kangaroo with explosives and painting it with the Islamic State symbol before setting it loose on Australian police officers. The documents don't suggest the alleged kangaroo plot was linked to the ANZAC Day plot.

Police say Besim was motivated by an extremist ideology and had expressed support for terrorist organizations, particularly the Islamic State movement.

Last year, a British court sentenced a 15-year-old boy from Blackburn, in northwestern England, for his part in the plot.

Besim has been in custody since his arrest last year. He is scheduled to return to court in August for a pre-sentence hearing.