"You do not belong here - go to Bangladesh. If you do not leave we will torch your houses and kill you," Myanmar security forces announced through megaphones.
But many Rohingya Muslims never got the chance to leave, according United Nations investigators, who have found that well-organised, co-ordinated and systematic attacks in Myanmar's Rakhine State were not only intent on driving an entire population out of Myanmar, but to prevent them ever returning home.
Shocking testimonies cited by the UN's Human Rights Office, obtained from survivors who reached Bangladesh, will intensify pressure on countries like Australia to impose sanctions on Myanmar and cut ties with the country's generals.
A 12-year-old girl from Rathedaung township in Rakhine State told how Myanmar security forces and Buddhist vigilantes surrounded her family's house and started shooting.
"It was a situation of panic - they shot my sister in front of me, she was only seven years old," the girl was quoted as saying in a UN report released on Thursday in Geneva.
"She cried and told me to run. I tried to protect her and care for her but we had no medical assistance on the hillside and she was bleeding so much that after one day she died???.I buried her myself."
A 26-year-old mother said when she woke up at 3am her house was on fire.
"There was chaos everywhere, they were shooting to kill us, they took women and dragged them away to rape them," she said. "They did not spare anyone - even children were beaten and tortured."
A 25-year-old woman described shootings in her village as a massacre.
"Women were collected and taken away - they were raped in front of us, in front of their families," the woman said.
"The [four men] in uniform took my sister when we were hiding in the hills???they raped her in front of us as we were hiding behind trees," she said. "She was crying but my father could not help her as we had to be quiet so they did not notice us. It was horrible and she had pain and was bleedings for days."
The report cited witness accounts of Rohingya victims, including children and elderly, being burnt to death inside their homes. It detailed evidence of children suffering severe beatings, stabbings and killings.
The report described a strategy to "instil deep and widespread fear and trauma - physical, emotional and psychological" among the Rohingya population.
More than 500,000 Rohingya have fled to squalid refugee camps in Bangladesh since August 25, when Myanmar security forces said they launched an offensive in response to Muslim insurgent attacks on police posts and a military base.
But the report said the offensive started in early August, days before before the insurgent attacks, and that violence is ongoing, despite a claim by Myanmar's de facto leader Aung San Suu Kyi that the offensive ended on September 5.
The report detailed the destruction by security forces of houses, fields, food-stocks, crops, livestock and even trees to "render the possibility of the Rohingya returning to normal lives and livelihoods in the future in northern Rakhine almost impossible".
"It also indicates an effort to effectively erase all signs of memorable landmarks in the geography of the Rohingya landscape and memory in a way that a return to their lands would yield nothing but a desolate and unrecognisable terrain," the report found.
The report pointed to evidence that Myanmar security forces have targeted "teachers, the cultural and religious leadership and other people of influence in the Rohingya community in an effort to diminish Rohingya history, culture and knowledge."
Investigators found it was "highly likely" that Myanmar security forces have planted landmines along the border in recent weeks to prevent Rohingya from returning, citing doctors treating injuries.
UN Human Rights chief Zeid Ra'ad al-Hussein urged Ms Suu Kyi's government to immediately end its "cruel" security operation.
He said by denying more than one million Rohingya their political, civil, economic and cultural rights, including the right to citizenship, the government's actions appear to be a "cynical ploy to forcibly transfer large numbers of people without the possibility of return".
UN and international aid agencies have described the situation in the Bangladesh camps as an emerging catastrophe with children and women the most vulnerable to disease, starvation, trafficking and sexual violence.
"The health and sanitation conditions are critical and described by on-site medical doctors as a perfect storm in the making," the UN report said.
Thousands more Rohingya are crossing the border each day in what has quickly become the largest movement of a civilian population in Asia since the 1970s.
The Turnbull government has resisted growing calls to consider punitive action to pressure Myanmar to end the atrocities, which human rights group say amount to crimes against humanity.
