South Australian high school student in a serious condition after being stabbed

A 17-year-old girl is in a serious condition after being stabbed at Renmark High School in South Australia's Riverland region.

Key points:

Student stabbed at Riverland school
Police and paramedics called just before 2:40pm
An 18-year-old student has been arrested

Police and paramedics were called to the school — which was placed into lockdown — just before 2:40pm.

Police arrested an 18-year-old female student.

Paramedics and staff treated the victim shortly before police arrived.

The SA Ambulance Service said the injured student was transported to Riverland General Hospital in Berri.

The ABC understands the students involved were in Year 12.

Students moved to gym during incident

One student told ABC Riverland that teachers kept other students in the gym for their last lesson until it was safe to leave.

"Thinking about it, someone got stabbed, it was scary, but the teachers kept us calm," she said.

"They had to keep us calm, safe in the gym. I think I felt safe in the gym."

The exterior of Riverland General Hospital

Parents said the school had not informed them of the incident.

In a statement the South Australian Education Department said it was working to ensure support for students and staff and it did not believe there was a "specific threat to the wider school community".

"The Department for Education is liaising with the school to ensure appropriate responses are put in place, including counselling and support for students and staff," the statement read.

"An assessment is being made as to whether additional security measures are required.

"The lockdown has been lifted and the general student population released to go home."

Renmark High School principal Mat Evans published a letter for parents on the school's Facebook page confirming the lockdown.

"We share your shock at this event which we are treating with the utmost seriousness," he said.

"While the police investigation is taking place I am limited in the information I can provide however I will attempt to answer any questions you may have."