A teenager has been taken into custody after he allegedly fired gunshots into a school in Perth's northern suburbs, forcing students and teachers to take cover and the college to be placed into lockdown.
Police said the 15-year-old fired at least three shots just before midday local time at Atlantis Beach Baptist College in Two Rocks, about 60 kilometres north of Perth.
WA Police Commissioner Col Blanch said police had seized two rifles after the incident, one a .243 calibre and the other a .22.
He said Major Crime Squad detectives were questioning the teenager, who was understood to be a former student.
'I've never seen anything like it'
Commissioner Blanch said the rifles were seized from a black four wheel drive at the scene.
"We found three shells, we believe three gunshots were fired and we at least know one of them did hit a school building," Commissioner Blanch said, adding the building was occupied at the time.
Commissioner Blanch said the bullet penetrated the wall.
The commissioner said he had never seen anything like it in his policing career, and said the investigation into the incident would be comprehensive.
"When I heard the reports of what had happened today, it really shocked me that this had occurred in Western Australia," he said.
"This is one of the ... rarest incidents in Australia, as police commissioner I've never seen anything like it here in WA or anywhere in Australia for that matter in my time as a police officer.
"We will certainly look into every aspect of this investigation to understand how a 15-year-old, a 15-year-old person is allegedly in possession of two long-armed rifles and has shot into a school in these terrible circumstances."
Commissioner Blanch said it was believed the firearms were registered to the boy's father.
He said the boy's parents would be questioned by police, and forensic officers were at the family home collecting evidence.
Major Crime would go through the boy's electronic devices and question any associates, he said.
"How does a 15-year-old get hold of two lethal weapons and fire them in a school area?"
No injuries reported
Police remained at the scene on Wednesday afternoon and said there was no ongoing risk to the public.
All staff and students at the school have been accounted for, and there have been no reports of injuries.
The school was immediately placed into lockdown and a steady stream of parents and grandparents arrived to collect children.
'We didn't know it was a gun'
Student Hunter McDermott said he heard "popping sounds" as the incident occurred.
"I was worried, but I wasn't crying," he said.
"[The school] handled it pretty well.
"We heard some popping sounds but we didn't know it was gunshots.
"There was an announcement saying we were going into lockdown and we didn't know if it was a drill or a real thing."
Hunter's grandfather John Walton said he had been worried while waiting to find out if his grandchildren were ok.
"We had two in there, we were a bit worried 'til we got out here and found out that police told us that they were all fine," he said.
"The rest has been waiting to get the kids out now."
Trauma for parents
Commissioner Blanch praised teachers and students who called triple 0, including a 12-year-old, and said the information they provided had been invaluable for first responders.
He said parents had been informed of the situation via SMS.
"You can only imagine the traumatic nature of parents arriving to know if their kids were ok," he said.
"I think these poor kids … it was the unknown for those kids.
"They didn't know what they were facing, the teachers didn't know what they were facing."
He said staff had remained calm and followed protocols, helping police bring the incident to a peaceful conclusion.
"[It's] the best outcome we could have hoped for," he said.
Premier expresses shock
WA Premier Mark McGowan issued a statement, saying "guns have no place in schools".
"My thoughts go out to the students, staff and families caught up in today's terrifying events, and to the wider Two Rocks community," he said.
"I can't imagine what it must have been like for children and teachers to hear the gunshots.
"I want to acknowledge the bravery shown by all the children, staff and parents at Atlantis Beach Baptist College."
"Thank you to the teachers, staff and police for their courageous and well managed response.
"These are scenes that we never want to see in Western Australia."
A spokesperson for the school said they had no immediate comment on the incident.
The ABC understands the neighbouring Cuddles Early Learning and Childcare centre in Two Rocks was in lockdown for some time, but a spokesperson for the facility said the lockdown had since lifted.
Atlantis Beach Baptist College is a private school catering for children from kindergarten to Year 10. It opened in 2017.
In a letter to parents, the college board chair Mike Smith announced the school would be closed on Thursday, but would reopen on Friday "under a modified teaching program" with counsellors available.
"The college board would like to thank the staff, administration team and the Western Australian Police for the way in which this incident was managed," Mr Smith wrote.
The college will reopen fully on Monday.