They trek for miles along a dangerous route -- risking drowning, disease and capture by the military -- to cross the border into neighboring Bangladesh, where refugee camps provide temporary shelter.
Tens of thousands of members of Myanmar's Muslim minority have left in this fashion, and their treatment may amount to "crimes against humanity," warns UN Special Rapporteur Yanghee Lee.
"When there's 77,000 people running away from their home towns, leaving everything ... the international community should really step up to the plate," she told CNN.
Lee has visited northern Rakhine State, which has been largely off limits to journalists and NGO workers since early October, and spoken to many refugees.
"What really struck me was when old men started to break down in tears in front of me and sob," she said, when interviewed on CNN's Newstream on Monday. "(They were) telling me they've seen their whole family killed in front of their eyes."
Myanmar government spokeswoman Aye Aye Soe said the administration is "deeply concerned by reports of potential human rights abuses and have already set up an Investigation Commission led by Vice President U Myint Swe."
Violence
"What is happening in Rakhine now is only security clearance sweeps being carried out with restraint and within rules and regulations against armed perpetrators," she said. "The instigators are using this situation to portray a disproportionate picture of 'genocide' and 'ethnic cleansing'."
The violence began on October 9, when according to state media, a group of around 300 armed men attacked soldiers and police, sparking an intense crackdown by the Myanmar military.
"We attacked them using our machetes, swords, and knives, and we seized their weapons to use against them," Atah Ullah -- leader of the Harakat al-Yaqeen, or "Faith Movement," which carried out the attack -- told CNN earlier this year.
"We, the vulnerable and persecuted people, have asked the international community for protection against the atrocities by the government of Myanmar, but the international community turned its back on us," he said. "Finally, we cannot take it anymore."
Abuses
With the Myanmar military arresting hundreds of people in Rakhine, deploying attack helicopters and allegedly setting fire to villages, thousands of Rohingya refugees have poured over the border to camps in Bangladesh.
"I would not use (the word genocide) right now but it could amount to crimes against humanity," said Lee.
She called on the international community to "walk the talk" on Myanmar, adding that Aung San Suu Kyi -- the country's long term democracy icon and de facto head of state -- "could and should speak up a little more."
"It is important that the Investigation Commission is allowed to complete its work, and to demonstrate that Myanmar's own institutions are able to address our human rights challenges," Aye Aye Soe said.
"In the meantime, we will continue to seek long term solutions to bring about lasting peace and stability in Rakhine."