BANGKOK (AFP) - Decades of discrimination have left the Muslim Rohingya stateless, scattered around the globe and viewed by the United Nations as among the most persecuted minorities on the planet.

About 800,000 Rohingya live in Myanmar, according to the UN, mostly in western Rakhine state, which has been hit by fierce communal violence since June that has left about 150 dead and caused tens of thousands to flee their homes.

Confined mainly to three districts - Maungdaw, Buthidaung and Rathedaung - they have long been treated as "foreign" by the government and many Burmese, a situation that activists say has led to a deepening alienation from Rakhine's Buddhists.

Images of squalid camps and reports of perilous attempts to flee to other countries in rickety boats have drawn international attention to their plight in recent years, but living conditions have scarcely improved. Forced labour, restrictions on freedom of movement, lack of land rights, education and public services were listed as among the limitations placed on the group, the United Nations refugee agency (UNHCR) said in a report published in December last year.

"The Rohingya are virtually friendless amongst Myanmar's other ethnic, linguistic and religious communities," the UNHCR report said.

Speaking a dialect similar to that spoken in Chittagong in southeast Bangladesh, the Muslims are viewed with hostility by many in Rakhine state, who view them as illegal immigrants from Bangladesh and refer to them as "Bengali". That animosity extends outside the state and even includes key figures in the democratic movement, long supported by the international community, which has warned the unrest and displacements pose a threat to Myanmar's reforms.

There have also been a series of recent anti-Muslim protests by Buddhists in the country, sometimes led by monks, amid perceptions of a threat to the majority Buddhist religion and fears over extremism - accusations the Rohingya strongly deny.

Neighbouring Bangladesh - where the UN estimates there are at least 230,000 Rohingya - sees the group as a burden on its strained finances and the refugees are blamed for all sorts of crimes in the southeast of the country ranging from petty theft to drug trafficking.

Bangladesh, which has mobilised extra patrols along its river border in response to the latest violence, drew UN criticism after it turned back boatloads of Rohingya, mainly women and children, after June's unrest.

Two massive waves of refugees, of approximately 250,000 people each, flooded across the border into Bangladesh in 1978 and 1991-92. Large scale repatriations ensued, with the UN questioning the "voluntary" nature of the measure.

In recent years, other Rohingya migrants have undertaken the dangerous voyage by boat towards Malaysia or Thailand, whose navy has, in the past, been accused of towing them back out to sea.

Hundreds of thousands of Rohingya are now thought to live outside Myanmar, including communities in Pakistan and around 400,000 in Gulf states, according to the UNHCR report.

Many are also now fleeing to Malaysia, where the UN says around 24,000 are registered. Rights groups say there may be thousands living unregistered in the country.

Myanmar has a multitude of ethnic groups, many of whom have conducted sporadic armed rebellions since independence from Britain in 1948. But the Rohingya are not officially recognised, partly owing to a 1982 law stipulating that minorities must prove they lived in Myanmar prior to 1823 - before the first Anglo-Burmese war - to obtain nationality.

Representatives of the Rohingya say their people were in Myanmar long before then, but while there have been suggestions that citizenship could be granted to those with a long-standing link to the country, judging proof of a Myanmar heritage could pose an intractable challenge for authorities.