Government troops are slaughtering the Rohingya and driving them out of Myanmar. Why are these people so hated? Here's everything you need to know:

What's going on?
Hundreds of thousands of desperate Rohingya people are fleeing a vicious military purge in Myanmar (formerly known as Burma). Troops have burned scores of villages, beheading men, raping women, and even killing children. In some places, Buddhist militias and mobs have joined in the attacks against the Muslim-majority Rohingya. The Myanmar army and government call their assault a counterterrorist operation, but the U.N. has labeled it a "textbook example of ethnic cleansing." With more than 420,000 people chased into Bangladesh since August and tens of thousands following them every week, the exodus is the world's most rapid and intense refugee crisis since the 1994 Rwandan genocide. The influx of brutalized families has overwhelmed aid efforts, and thousands of hungry people are camping in the open, exposed to monsoon rains. About 60 percent are children, and many have lost their parents to massacres back home. "The sheer scale of it is beyond belief," Tejshree Thapa of Human Rights Watch told Newsweek. "I've never seen a group this devastated, this destroyed."

Who are the Rohingya?
They are often described as the world's most persecuted people. Muslims have lived in the coastal Rakhine area, separated from the rest of Myanmar by a mountain range, since at least the 12th century. The Rohingya are believed to be descended from those early Arab and Mughal traders. But since populations have been driven back and forth across the border of what is now Bangladesh at least four times since the late 1700s, there was significant mixing with South Asian Muslims. During more than a century of British colonial rule, from 1824 to 1948, many Muslims in what is now India and Bangladesh relocated to Burma, then a British Indian province, to work, and they, too, were absorbed into the Rohingya. The Rohingya language, Rohingyalish, is close to the Chittagonian dialect spoken in southern Bangladesh.

Why do the Burmese reject them?
Mistrust goes back decades, and has its roots in ethnic and religious enmity as well as political differences. During World War II, the Rohingya supported the British while Burmese nationalists supported the Japanese. The British promised the Rohingya their own state but did not deliver. In 1948 the Rohingya were left in newly independent Burma amid a Buddhist majority that now saw them as disloyal and potentially dangerous foreigners. When a military junta took over Burma in 1962, it labeled the Rohingya "Bengalis" and excluded them from citizenship, leaving them stateless, with no access to government health care, education, or most jobs. Periodic waves of mass persecution over the following decades have given rise to a Rohingya resistance movement, and growing radicalization among Myanmar's young Muslim men. In recent years, the radicals have formed the Arakan Rohingya Salvation Army (ARSA), known locally as Al Yaqin, or the "Faith" movement.

How did the current purge begin?
ARSA militants killed nine border police last October. The enraged government sent troops pouring into Rakhine state, and refugees say the soldiers raped, killed, and burned their way through Rohingya villages. The current exodus began in earnest in August, after ARSA militants attacked police posts, killing 12 and sparking the ongoing massive crackdown. Many fleeing Rohingya are furious at ARSA, who remain a small minority of their population. "We are the ones who are suffering because of Al Yaqin," said refugee Noor Kamal. "They disappeared after the attack. We were the ones left behind for the military to kill." Even the country's civilian leader, Nobel Peace Prize winner Aung San Suu Kyi, has cited the ARSA attacks in condemning the Rohingya as "terrorists."

What is Bangladesh's position?
Bangladesh is one of the few countries that never ratified the U.N. Convention on Refugees, and has consistently insisted that the Rohingya must return to Myanmar. Prime Minister Sheikh Hasina said last week that her country is currently sheltering more than 800,000 Rohingya. She has called on the U.N. to supervise safe zones in Rakhine so those families can "return to their homeland in safety, security, and dignity." But that will be difficult: In the same speech, Hasina accused Myanmar of laying land mines along the border to prevent the Rohingya from returning.

And the international community?
The U.S., Turkey, Saudi Arabia, and other countries have strongly denounced Myanmar's crackdown and pledged millions in emergency aid. But Myanmar won't allow aid agencies in to help the 800,000 displaced Rohingya still trapped in Rakhine. Meanwhile, in Bangladesh, the U.N. refugee agency is rushing in supplies to feed and shelter the masses of people, mostly by expanding the existing camps housing Rohingya driven out in past purges. But caring for so many displaced people at once is an overwhelming challenge, and hunger and disease are rampant, while clean water and toilets are virtually nonexistent. "When you walk through the settlement, you have to wade through streams of dirty water and human feces," said Kate White, the emergency medical coordinator of Doctors Without Borders. "A public health emergency could be just around the corner."

An international icon's silence
Aung San Suu Kyi won international acclaim for her principled opposition to the authoritarian regime that has ruled Myanmar for decades, and for her demand for democratic elections. But the country's de facto civilian leader, now 72, has deeply disappointed many of her admirers by refusing to criticize the military for its brutal oppression of the Rohingya. Suu Kyi, a Buddhist nationalist, said the Muslim group had brought the crackdown on itself by supporting terrorism, and claimed, against all evidence, that security forces were exercising restraint and avoiding "the harming of innocent civilians." Critics say she has become complicit in the ethnic cleansing and did not deserve her Nobel Prize. Her defenders contend that Suu Kyi has to be circumspect, because the military would use the Rohingya issue to undermine her popularity and by extension civilian rule, only recently restored. "The army, they are watching her every word," said U Win Htein, a former Myanmar military officer. "One misstep on the Muslim issue, and they can make their move."