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Eight children were found dead after a stabbing at their Australian home Friday, in what their country’s prime minister described as an “unspeakable crime.”

The 34-year-old mother of seven of the children, who ranged in age from 18 months to 14 years old, was being treated in hospital.

Queensland Police were called to the home in the Cairns suburb of Manoora at 11:20 a.m. Friday local time (8:20 p.m. ET Thursday) after a 20-year-old relative — described locally as an elder sibling of the victims — found the bodies.

“They’re only babies,” relative Lisa Thaiday told Channel 7 News. “Just shocking … you know, eight children gone."

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Both the victims' mother and the 20-year-old man were assisting investigators but nobody else was currently being sought over the killings, Queensland Police spokesman Joe Marsden said.

"This is certainly a tragic and traumatic event"

The Cairns Post reported that the children had been stabbed and suffocated but Marsden could not confirm that, saying investigators were awaiting the outcome of autopsies.

Detective Inspector Bruno Asnicar added: “As it stands at the moment, there's no need for the public to be concerned about this other than the fact that it's a tragic, tragic event. We don't have any persons that are formally suspects at the moment. We're speaking to a range of people. And we're speaking to anybody that's even had associations with this family in the last two to three days."

He added: "This is certainly a tragic and traumatic event, with so many people deceased in one place. It's right up there with one of the most serious things I've ever had to deal with."

Superintendent Russell Miller asked for the local community to remain calm. “Obviously it’s going to be a complex investigation and it’s going to take time. I’m sure at the end of the day we’ll be able to get the answers the community needs.”

Australian Prime Minister Tony Abbott noted that the killings came in the same week as the 16-hour Sydney café siege that left two hostages and a gunman dead.

The events in Cairns today are heartbreaking & all parents would feel a gut-wrenching sadness at what has happened. — Tony Abbott (@TonyAbbottMHR) December 19, 2014

"These are trying days for our country," Abbott said.

Public vigils were held in Cairns on Friday night. “Please join us as we pull together as a community in this time of grieving,” Pastor Michael Dalla Vecchia from City Church Cairns posted on Facebook.