Attacks by Rohingya Muslim insurgents on the Myanmar security forces in Rakhine State triggered a response by the army and Buddhist vigilantes so brutal a senior U.N. official denounced it as a textbook example of ethnic cleansing.

Days, weeks, and months after the Aug. 25 violence, more than 600,000 Rohingya fled to Muslim Bangladesh, trekking over mountains and through forests and rice fields inundated by monsoon rain.

Many of the refugees were traumatized, exhausted and hungry, some wounded by bullets, knives or clubs, many with burns. Many women said they had been raped.

All of the refugees brought accounts of a campaign of murderous violence and arson by the Myanmar security forces and Buddhist civilians that they believed was aimed at driving them out of the country.

Mostly Buddhist Myanmar denies the accusations.

Myanmar says the rebels responsible for the Aug. 25 attacks on about 30 security posts and an army camp - the Arakan Rohingya Salvation Army - are terrorists and it is they who unleashed most of the violence and arson that reduced hundreds of Rohingya villages nestled in emerald-green rice fields to ash.

The Rohingya have long faced discrimination and repression in Rakhine State where bad blood with ethnic Rakhine Buddhists, stemming from violence by both sides, goes back generations.

Rohingya are not regarded as an indigenous ethnic minority in Myanmar — the government even refuses to recognize the term "Rohingya," instead labeling them illegal immigrants from Bangladesh. Most have been denied citizenship under a law that links nationality to ethnicity.

They have long lived under apartheid-like conditions, with little access to even the limited opportunities in education and employment open to their Buddhist neighbors in one of Myanmar's poorest regions.

About 1 million Rohingya were believed to have been living in Rakhine State before the latest violence. Bangladesh was already home to 400,000 of them who had fled earlier repression.

The new arrivals, many landing by boat after being ferried across a border river, crammed into the existing refugee camps in the Cox's Bazar district, many camping out in the rain — lucky ones able to string up a piece of plastic — beside muddy tracks.

Bangladesh, one of the world’s poorest and most crowded countries, initially said the Rohingya were not welcome and ordered border guards to push them back.

But it quickly changed its stand in the face of the scale of the exodus and began gearing up, with the help of U.N. and other aid agencies, to cope with the fastest-developing refugee crisis the world had seen in years.

The crisis has raised grave doubts about Myanmar's transition from military-ruled pariah to budding democracy, and about the commitment to human rights of the democracy leader who struggled to end nearly 50 years of harsh military rule - Aung San Suu Kyi.

The generals remain in full charge of security under a constitution they drafted, even though Suu Kyi runs the government.

Analysts say Suu Kyi has to avoid angering the army and alienating supporters by being seen to take the side of a Muslim minority that enjoys little sympathy in a country that has seen a surge of Buddhist nationalism.

Nevertheless, the failure of the Nobel peace laureate to speak out forcefully in defense of the Rohingya would seem to have irreparably damaged her reputation overseas.

The international community is demanding that the Rohingya be allowed to go home in safety, and Bangladesh and Myanmar have begun talks on repatriation, but huge doubts remain about the Rohingya ever being able to return in peace to rebuild their homes and till their fields.