One woman is in a critical condition in hospital and another is in a stable condition after an alleged multiple stabbing at the Australian National University campus.
Students, staff and members of the public are being told to stay away from Fellows Oval.
ACT police said two people have been taken to hospital with stab wounds, both are 20-year-old female students at the university. One is in a critical condition, and the other is in a stable condition, as of 5.30pm.
A third person, a 34-year-old man who police originally said had been taken to hospital, was allegedly assaulted, and received minor injuries, but did not require hospitalisation.
Several police officers are at the scene, investigating the incident, which happened about 2.45pm on Monday.
"A 24-year-old male, who is not believed to be a student of the university, is in police custody. He has not been charged at this time. No other people are being sought by police," police said.
"No specific motive for the incident has been identified."
Police are asking anyone with mobile phone footage of the incident to provide it to officers at the City Police Station as soon as possible.
A woman on a stretcher was seen being taken away by ambulance officers near the Chifley Library.
A worker at the ANU reported the incident. It's understood that the police and the university authorities were liaising about the matter.
An ANU spokesman confirmed there had been a serious incident.
"Police are at the scene and have the situation under control, with an individual in custody," the spokesman said. "Please stay away from Fellows Oval."
The incident is believed to have happened at the Chifley Library on the campus, whether inside or outside is unclear.
One person at the scene said there were about 10 police cars and seven ambulances. The head of ANU security was also on site. The police were interviewing students there.
The ANU has emailed students, asking them to stay away from the area.
"There was an incident on the ANU campus this afternoon. An individual is in police custody and there is not threat to the community," the email reads.
"Please continue to stay away from Fellows Oval.
"We encourage anyone who has been distressed by this to make use of the following resources.
"Staff can access support and counselling through the Employee Assistance program ... Students can access support via ANU Crisis Support Line on 1300 050 327 or via SMS Text message service... Updates to follow on ANU channels."
Any witnesses who have not already spoken to police are asked to attend City Police Station where ACT Policing representatives will be able to assist or contact Crime Stoppers on 1800 333 000 or via www.crimestoppers.com.au referencing P219341.
