Two police officers have serious burns as a result of a gas bottle explosion at a Melbourne flat that also injured four others.
Police were called to a Middle Park flat about 7.15pm (NZT) on Saturday after reports of a man threatening self-harm.
As firefighters and police entered the flat via the balcony using a ladder, there was a large explosion caused by an exploding gas bottle.
The intensity of the explosion shattered the windows of the apartment.
Deputy Commissioner Tim Cartwright said police believed the incident to be a suicide attempt rather than a malicious attack.
''This is probably the worst nightmare we have,'' Cartwright said. ''I find this a tragedy, it cuts very deep.''Our members deal with people with mental illness every day ... You ask them to go and look after the community and as a result, this happens.''
Cartwright said the family of the police officers were traumatised by the event.
Two junior female officers who had less than four years on the job received serious burns to their faces and upper bodies and are in serious but stable conditions after surgery at The Alfred Hospital.
A male sergeant in his 50s is in stable condition at the hospital.
Two firefighters were hospitalised with non-life-threatening injuries.
One was released from hospital on Saturday night, while the other remains at the Royal Melbourne Hospital in stable condition.
A 40-year-old male resident remains in a serious but stable condition at The Alfred Hospital and is under police guard.
Police said the man was not in a fit state to talk but could face charges.
Mr Cartwright said a medical practitioner had offered assistance at the scene to hose down the injured police members with a garden hose.
Psychologists, welfare officers and a police chaplain will speak with the police officers and their families.
Police will remain at the crime scene until Monday to investigate.