The soldiers arrived in the Myanmar village just after 8 a.m., the villagers said, ready to fight a war.

They fired shots in the air, and then, the villagers claim, turned their guns on fleeing residents, who fell dead and wounded in the monsoon-green rice paddies. The military's retribution for a Rohingya militant attack on police posts earlier that day had begun.

Mohammed Roshid, a rice farmer, heard the gunfire and fled with his wife and children, but his 80-year-old father, who walks with a stick, wasn't as nimble. Roshid said he saw a soldier grab Yusuf Ali and slit his throat with such ferocity the old man was nearly decapitated.

"I wanted to go back and save him, but some relatives stopped me because there was so many military," Roshid, 55, said. "It's the saddest thing in my life that I could not do anything for my father."

The Myanmar military's "clearance operation" in the Maung Nu hamlet and dozens of other villages populated by the country's ethnic Rohingya minority triggered an exodus of an estimated 400,000 refugees into Bangladesh, an episode the United Nations human rights chief has called "ethnic cleansing." The tide of refugees is expected to grow in the coming days.

The newly arrived refugees - dazed, clutching their belongings, some barefoot in ankle-deep mud - have overflowed an existing camp and put up makeshift shelters. Others simply sit on the roadways, fighting crowds as large relief trucks fling down bags of rice or bottles of water.

Rights groups say it will take months or years to fully chronicle the devastation they are leaving behind in the nation also known as Burma. Satellite photos show widespread burning, witnesses recount soldiers killing civilians, and the government itself said 176 Rohingya villages stand empty. No total death toll is yet available because the area remains sealed by the military.

Nearly a dozen villagers from the Maung Nu hamlet who escaped recounted their last hours in their homes and the long journey that followed. They were interviewed for two days in Kutupalong refugee camp near the Bangladesh border, where they arrived last week. Fortify Rights, a Southeast Asia-focused human rights organization, estimates the death toll in Maung Nu and three nearby villages to be 150.

"I can't count how many," said Soe Win, a 10th-grade teacher. "We were all watching what the military did. They slaughtered them one by one. And the blood flowed in the streets."

The latest wave of violence began Aug. 25, when an emerging group of Rohingya militants, the Arakan Rohingya Salvation Army, attacked 30 police posts and an army base in Rakhine state, killing 12. The subsequent military crackdown has prompted hundreds of thousands of refugees to leave Buddhist-majority Myanmar, until recently ruled by a military junta where Rohingya have long faced denial of citizenship and other rights.

The International Rescue Committee estimates that eventually 500,000 will flee to Bangladesh, half of the known Rohingya population in the country, most of whom live in troubled Rakhine state. The area has long been riven by tensions between Buddhist villagers and the stateless Rohingya, who have been there for centuries but who are still considered by the government to be illegal immigrants, "Bengalis" from neighboring Bangladesh.

The crisis has prompted widespread outcry and condemnation of Burma and its de facto leader, Nobel laureate Aung San Suu Kyi. She and her government have said little about the plight of the Rohingya, except to reframe it as a national security matter as the new militancy has coalesced. On Monday, the U.N. High Commissioner for Human Rights, Zeid Ra'ad al-Hussein, called the exodus "a textbook example of ethnic cleansing."

In Maung Nu, a tiny hamlet of about 750 houses that sits along a narrow stretch of the slow-moving Mayu River, the Rohingya had long lived in relative calm, sipping tea with their Buddhist neighbors, villagers say.

But their peaceful coexistence ended on when Rohingya insurgents launched their attack on police posts. The military crackdown has continued unabated since then, black smoke scudding across the skyline visible in southern Bangladesh even this past week.

Mohammed Showife, 23, an auto mechanic, said on the first day of the assault he and his family had just finished their morning prayers and were preparing rice when three soldiers appeared in the yard, announcing their arrival with a strafe of machine-gun fire and telling them they had to leave their homes immediately.

"They said, 'You Bengalis come out from the house. You can go anywhere you want, but you can't live here,' " Showife recalled.

He and his family members scattered, and he stopped to help his neighbor Mohammed Rafique, 17, whose right hip had been run clean through by a bullet, back to front. They ran through a mob looting homes and soldiers setting fire to other dwellings with shoulder-fired rocket launchers. Many took refuge in the jungle, where the dense foliage, thick after the monsoon, provided cover.

Once there, some of the women sat silently weeping. Others just looked at each other: What would they do now? They tried to attend to Rafique's wound with boiled water and torn strips of clothing.

The first night came, an uneasy darkness settled in, the sky flickering with fire and shadows. They did not know then there would be five nights more.

On the second day, a businessman hiding in his house got a call from a tall, skinny Army sergeant they all knew and called "Bajo," who had often dined in his home.

Bajo said the military was going to be requisitioning one of his passenger boats. Given the circumstances, Mohammed Zubair, 40, felt he had no choice but to give it to them. He sent the boat with the captain to the jetty at the nearby army camp. The officers accepted the keys with the warning for the captain: "You will also be killed." The boat driver eventually escaped unharmed with the others.

Zubair said he had followed to see what was to become of his vessel. He says he watched in horror as the military began stacking dead bodies on the boat, one after the other, like lumber, including two 13-year-old boys he knew well.

"I fainted from seeing this," Zubair said. He believes they were dumped in the river.

On the third day, Rafique's mother, Khalida Begum, 35, had grown tired of moving from house to house with her four other children, desperate for news of her son. She raised them on her own on a tailor's salary after her husband died years ago, so she and the children are unusually close. They managed to make it to the jungle, where she saw Rafique lying motionless underneath a tree.

She ran to him and covered his face with kisses, joyfully, as he emerged from his fevered haze. At first he was so disoriented that he did not recognize her. But soon they were both crying.

On the sixth day, the residents of Maung Nu decided as a group they would start walking north to the border with Bangladesh, fearing the danger was growing.

They walked for eight days with few provisions, eating banana leaves and drinking water from streams. The children whimpered. Showife carried Rafique on his back, the teen drifting in and out of consciousness. After a while, their legs began to swell.

Finally, they reached a crossing high on a hill marked by a simple pillar that they understood meant they had arrived in Bangladesh. It was 4:30 in the afternoon. It was raining. Before them was a new city of refugees, thousands of temporary tents, bamboo poles covered in black plastic sheeting.

The villagers knew there would be tough times ahead as they descended the hill, slipping a little in the mud. For days afterward, when some of them closed their eyes, they could see the lifeless bodies of their neighbors and hear the ring of gunfire in their ears.

But at the pillar, a little cheer went up.

"I was very happy," Khalida Begum said. "I was crazy, I was excited, I thought - now we are safe."

Days later, Khalida Begum's eyes filled with tears when she recounted this moment. It was the first time she had allowed herself to believe what the others who helped Rafique out of the village had hoped for: that her son would live.