8 children found stabbed to death in Australia (Roundup)

Eight children as young as 18 months to 15 years were found stabbed to death at a house in Australia's Cairns city Friday, with neighbours saying they heard the kids screaming in the morning.

A 34-year-old woman was found injured in the house, whom police confirmed to be the mother of seven of the eight dead children. She was being treated for stab wounds to the chest and neck, the Cairns Post reported.

The incident came to light when the children's 20-year-old sibling arrived home.

Police have stated they are not looking for anybody else in relation to the deaths and have yet to lay charges.

Police also said the incident is not believed to be related to terror.

People living around the house heard shouting and screaming coming from the residence of the victims around 10 a.m., the report said.

The woman is "assisting police with their inquiries" and "not in custody", police said.

It is not clear whether a second person taken to hospital is the children's stepfather, who lived at the house.

Police have not confirmed how the children were killed.

Australian Prime Minister Tony Abbott described the killing of the eight children as an "unspeakable crime" and expressed grief over the incident.

"All parents would feel a gut-wrenching sadness at what has happened," the statement said.

"These are trying days for our country. Tonight, there will be tears and prayers for these children," he added

Neighbours of the family involved in the horrific tragedy have said they were friendly, quiet and kind.

A resident who lives directly behind the house said he had only met the woman and children a few times.

A mobile police facility has been established and officers from the Cairns Criminal Investigation Branch, child protection and investigation unit, and scene of crime and scientific section are conducting an investigation and examination of the scene.

This is the second shocking news to hit Australia in a week. Earlier this week, a gunman took hostage 17 people in a cafe in Sydney. Three people, including the gunman, were killed in the siege.