Australian police are on high alert in Victoria State.

Officers had asked an 18-year-old man to come to this Melbourne police station because his behaviour was "causing concern".

(SOUNDBITE)(English) VICTORIA POLICE CHIEF COMMISSIONER KEN LAY SAYING:

"This was a planned and agreed meeting that was to occur at the Endeavour Hills police station. When these two police officers approached him, they were stabbed, one very seriously."

One of the officers then shot dead the teen, whose passport had earlier been cancelled on security grounds.

(SOUNDBITE)(English) JUSTICE MINISTER MICHAEL KEENAN SAYING:

"I can advise that the person in question was a known terror suspect who was a person of interest to law enforcement and intelligence agencies."

Police say the man had been displaying a flag linked to the militant group Islamic State at a local shopping mall. Local media reported he had been shouting insults about Prime Minister Tony Abbott and the gove