(CNN) -- An Australian high school teacher caused a stir this week after asking her class to plan a terror attack that would kill as many innocent people as possible.
The teacher of society and an environment class told her pupils to plan a chemical or biological attack in Australia, the Australian Associated Press reported.
The students were instructed to explain how they would choose victims and were urged to devise a plan to kill as many innocent people as possible, the news agency reported.
The teacher canceled the assignment after a 15-year-old student objected to it.
But word of the assignment got out and became a hot topic on radio shows in Australia on Wednesday.
The principal of the school said the assignment was made by a young inexperienced teacher. The principal said he pushed to have the assignment canceled once he heard about it.
"This is one mistake by a hardworking, keen young teacher who is highly regarded by staff, students and community,'' Terry Martino, principal of the West Australian school, told the news agency.