When state security forces entered the western Myanmar village of Chut Pyin in the midafternoon Sunday, they weren't alone. According to the survivors who spoke with Fortify Rights, an international aid group, armed residents of a nearby village mingled with the troops — but they both had a common target.

Together, Fortify Rights says, the two groups wasted no time setting to work against the village's Rohingya, a predominantly Muslim ethnic minority in the country, paying no attention to whether their victims were men, women or children.

"My brother was killed—[Myanmar Army soldiers] burned him with the group" in a bamboo hut, one survivor told the group. "We found [my other family members] in the fields. They had marks on their bodies from bullets and some had cuts. My two nephews, their heads were off. One was six-years old and the other was nine-years old. My sister-in-law was shot with a gun."

Within a span of five hours, witnesses say more than 200 people were killed.

NPR is not able to independently verify claims in the group's report.

It has been roughly a week since the Arakan Rohingya Salvation Army, a Rohingya militant group also known as ARSA, launched coordinated attacks on security outposts in Rakhine state, near the border with Bangladesh. Scores of people died, most of whom were the attackers, but Myanmar's military says the violence in the days that followed has dwarfed last Friday's death toll.

Citing a statement posted on Facebook, The Associated Press reports 399 people have died in 90 clashes this past week — and all but 29 of the dead were insurgents, according to the statement.

International observers condemned the extremists' attacks last week, but they expressed particular alarm over the military crackdown on Rohingya civilians that has followed. Viewed with suspicion as collaborators with the militants, the Rohingya have often been treated brutally by the military in Buddhist-majority Myanmar, which doesn't consider them to be citizens. Earlier this year, the United Nations decried the "devastating cruelty" with which the military retaliated against civilians for a similar militant attack last October.

"About 1 million Rohingya live in Rakhine state, and they are almost entirely disenfranchised and need permission, for instance, to travel outside their own villages or to marry," NPR's Michael Sullivan and Ashley Westerman explained earlier this year. "Many are restricted to living in internment camps, segregated from the local Buddhist population."

And now, that long-precarious position appears to have been destabilized still further by the recent fighting — including the ferocious reprisals reported by groups like Fortify Rights. The aid organization says troops, police officers and even villagers armed with swords and knives have been involved in a series of mass killings and arson in pockets of Rakhine.

"The situation is dire," Matthew Smith, the group's CEO, said in a statement. "Mass atrocity crimes are continuing."

"The secretary-general is deeply concerned by the reports of excesses during the security operations conducted by Myanmar's security forces in Rakhine State and urges restraint and calm to avoid a humanitarian catastrophe."

The United Nations estimates that between the extremist attacks and the government's retaliatory crackdown, more than 27,000 Rohingya have fled over the border into Bangladesh in recent days, with an additional 20,000 "stranded between the two countries." Unnamed sources with the U.N. tell Reuters the number of Rohingya who have crossed into Bangladesh is closer to 38,000.

And they warn that those numbers are only growing.

"The worsening cycle of violence is of grave concern and must be broken urgently," said Yanghee Lee, the U.N. special rapporteur on the human rights situation in Myanmar. "I am concerned that these events will derail efforts to address the root causes of the systematic discrimination and recurrent violence in Rakhine State."

U.N. Secretary-General Antonio Guterres' office also released a statement on the violence Friday: "The secretary-general is deeply concerned by the reports of excesses during the security operations conducted by Myanmar's security forces in Rakhine State and urges restraint and calm to avoid a humanitarian catastrophe."

Far from a place of solace, the land across the border presents the fleeing Rohingya with its own set of dangers. For the refugees already in Bangladesh, thousands of whom fled the crackdown that followed October's attack, life is often confined to bleak camps held together with plastic sheeting and bamboo. And that's the case only for those lucky enough not to be turned away at the border.

Some do not even make it that far.

Bangladeshi officials say the bodies of at least two dozen people washed up on the banks of the Naf River separating the two countries, as Reuters reports.

"We believe they were Rohingyas," said the commanding officer of a local Bangladeshi battalion, according to the New York Times. "They died because their boats capsized when they were coming to Bangladesh by boat from Myanmar."

But many Rohingya fear still worse what awaits them if they stay put.

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