"With honour, they served."
That's how Australia is remembering two police constables gunned down along with a property owner, the highest number of police killed in a single incident in recent memory.
Constable Matthew Arnold, 26, and Rachel McCrow, 29, died along with neighbour Alan Dare, 58, after two men and a woman opened fire on them at a property at Wieambilla on the Western Downs.
Commissioner Katarina Carroll says the "absolutely devastating" attack was extremely emotional and challenging for Queenslanders.
"I know we are all thinking of the victims' families who are grieving at this difficult time," she told reporters.
"With honour, they served."
Premier Annastacia Palaszczuk said flags will fly at half-mast on government buildings across the state, while Brisbane's Story and Victoria bridges will be lit blue and white in mourning.
"Hopefully it will give the QPS family some comfort that the people of this state absolutely respect and appreciate every single thing that they do," she said.
"I doubt that this will bring much comfort to the families and loved ones of those who were killed.
"They were so young, so young, they were incredibly bright, these were absolutely callous, brutal acts."
The attack during a routine welfare check on a missing person was "beyond imagination", she said, and the sort of thing Australians usually heard about happening overseas.
"Our hearts just go out to the young constables who lost their lives in such a tragic ... it's just ... words cannot describe," Ms Palaszczuk said.
"When I was hearing about this and speaking to people involved, I just couldn't believe this was happening in our community."
Prime Minister Anthony Albanese said it was a rough day for all police and their families, and he praised their "public service at the highest level."
"This is not a price that anyone who puts on the uniform should ever pay," he said.
Federal Opposition Leader Peter Dutton, also a former police officer, said the attack would "send a shiver down the spine of any police officer".
"Of course, the police family is absolutely devastated," Mr Dutton said.
"People will be scarred from the experience. It's time for our community, for our country to come together around police and support them."
On the other side of the country, West Australian Police Commissioner Col Blanch said flags would be flown at half-mast in memory of the two constables, while the WA police union has donated $10,000 to a remembrance fund for the pair and organised for a number of Perth venues to be lit blue and white.
"I know WA Police officers have also felt the impact of the deaths, and many have reached out to their colleagues in Queensland to offer support," Mr Blanch said.
"All officers across Australia and New Zealand will be feeling a sense of loss today."
Police Association of Tasmania president Colin Riley said the killings had the hallmarks of a "targeted execution of police" and were very personal for his members.
"It triggers reflection by our members of the very real risks that we face every day doing our jobs, their own near misses that they have attended over the years and the possible consequences on their families," he said.
Australian Federal Police Association president Alex Caruana said the two Queensland officers would leave "a big hole" in the Western Downs community, and Australians should rally behind those affected.
"It won't just be the police family or the blue family, that'll be feeling it, it'll be the whole community, and they're going to need support, they're going to need support through this," he told ABC Radio Canberra.
