The systematic slaughter of civilians by security forces in Myanmar's Rakhine State has forced hundreds of thousands of stateless Rohingya Muslims to flee to Bangladesh, creating a humanitarian disaster not seen in Asia for decades.
Who are the Rohingya?
Historians say Rohingya Muslims have lived in Myanmar, also known as Burma, since the 12th century.
They are descendants of Muslim migrants from India and China as well as earlier Arab settlers. Their religion is a Sufi-infused Sunni Islam.
Because the Myanmar government restricts their educational opportunities, many pursue fundamental Islamic studies in mosques and religious schools present in most villages. They speak a dialect of Bengali, which is spoken in Bangladesh and parts of India. Their dialect is distinct to other languages spoken in Rakhine.
About 1.1 million Rohingya were living in impoverished state before the latest outbreak of violence but they are not considered one of 135 official ethnic groups.
Their rights to marry, study, travel and have access to health services are restricted.
What sparked the exodus of Rohingya to Bangladesh?
The world's newest Muslim insurgency revealed itself in western Myanmar last year when militants attacked Myanmar police posts. New attacks took place on August 25, the day a state-appointed commission of inquiry headed by former UN chief Kofi Annan released its report into previous bloodshed. Several police were killed.
Since the 1970s Rohingya have been have been targeted in a cycle of violence by Buddhists and Myanmar security forces, prompting the UN to describe them as among the world's most persecuted people.
According to the International Crisis Group, a committee of Rohingya emigres with experience in guerrilla warfare oversees the militants from Mecca. Its leader Attaullah Abu Ammar Jununi was born in Pakistan and raised in Saudi Arabia. Muslim militants started to secretly train in guerrilla warfare after ethnic riots in 2012 killed hundreds of Rohingya.
ARSA militants are now pitted against Myanmar security forces in Rakhine. Rohingya were stripped of their citizenship in 1982 as part of decades-long persecution that has denied them basic rights, including freedom of movement.
In 2012, they were the target of violent Buddhist mobs that forced more than 140,000 from their homes into squalid camps.
In March 2014, the Myanmar government banned the word Rohingya and asked for registration of the minority as Bengalis in the country's first census in three decades. It meant that 1.3 million Rohingya in Arakan, also called Rakhine state, were not included in the census.
On April 2015, the government formally rescinded the temporary ID or "white cards", the last form of official government identification for Rohingya, stripping them of voting rights linked to the cards.
The Rohingya had hoped the election of Nobel Peace laureate and democracy champion Aung San Suu Kyi in November 2015 would see a turnaround in hostility towards them from the new government in Naypyidaw and Buddhist groups. But violence against them has dramatically worsened since then.
A UN report in February 2017 accused Myanmar security forces of atrocities against the Rohingya that could amount to crimes against humanity.
Could the crisis spread beyond Myanmar's borders?
According to the International Crisis Group, a committee of Rohingya emigres with experience in guerrilla warfare oversees the militants from Mecca. Its leader Attaullah Abu Ammar Jununi was born in Pakistan and raised in Saudi Arabia. Some experts say more than one million Rohingya living in Rakhine were ripe for exploitation by foreign jihadists.
Rohingya do not have a history of radicalisation and there are no indications ARSA has been pursuing the goals of global jihadist groups. But Islamic State and other Islamic terror groups want to establish a foothold in the region, and that may change.
Unless Myanmar's security forces end their brutality in Rakhine and the government of Aung San Suu Kyi adopts a political response to the crisis, increasing numbers of Rohingya are likely to swing their support to the militants.
Why has Aung San Suu Kyi refused to speak up for Rohingya?
Although the country's de facto leader, Suu Kyi is sandwiched politically by the powerful Myanmar military, nationalist Buddhist-majority parties and an undemocratic Constitution. She says her government, swept into power at historic elections in 2015, cannot tell the military not to launch offensives.
Army generals see themselves as saviours of the country. Many Buddhists hate Rohingya and label them "Bengali" illegal immigrants. If Suu Kyi was to speak up for the Rohingya she would alienate her support base.
Why are neighbouring countries so worried?
The crisis divides Buddhists and Muslims across south-east Asia and South Asia. Anti-Buddhist protests have already been held across Pakistan, India and Indonesia.
The plight of Rohingya could become a lightning rod for existing underlying divisions between Muslims and non-Muslims in countries such as Indonesia, Malaysia and India, where hundreds of thousands of Rohingya are living, many of them after putting their lives in the hands of people smugglers to flee Rakhine. Politicians with domestic agendas could exploit the tensions.
Why is Australia concerned about in the situation?
Australia fears ongoing violence in Rakhine could spark a new wave of boat people - that's what happened in 2015 after an outbreak of violence in Rakhine prompted a flood of refugees.
One leading analyst warns the region could suddenly have to confront desperate Rohingya diaspora problem such as that of the Palestinian issue that has perpetuated violent conflict in the Middle East for 70 years.