Chiang Mai, Thailand - The mob that set upon and killed a group of Muslims riding a bus through western Myanmar on June 3 displayed a depravity normally the hallmark of the country's military. News reports that emerged in the wake of the incident, allegedly in response to the gang rape and murder of a Buddhist girl by three Muslim men days before, described the ten victims of a frenzied beating being urinated upon before the bus was set ablaze.

Comments that circulated the internet in the wake of the massacre were almost as shocking. "Killing Kalars is good!" one person said, using the pejorative slur that has become a popular and casual way of referring to Muslims of South Asian decent (one that state media also regularly employs). It mattered little that the men accused of the rape had already been arrested.

The attack was a rare incident; the reactions suggest however that heightened levels of resentment towards the presence of Muslims in Myanmar society exist on a much wider scale. This animosity is shared by senior figures in the government - current representative to the UN, Ye Myint Aung, once described the Rohingya, a Muslim minority in Arakan state who are singled out for particularly savage treatment, as "ugly as ogres", while since 1982 the government has denied them citizenship, claiming they are "illegal Bengali immigrants". Persecution of the group has been so protracted and debased that Medicins San Frontieres describes them as being among the world minority groups "most in danger of extinction".

While Myanmar's myriad ethnic groups have all suffered egregious treatment at the hands of the military government, which has sought to bring the country "under one flag", the fear of Muslims is a particular one. On the website of The Voice journal, which issued an apology after being bombarded with threats following its coverage of the massacre, one visitor wrote: "We should either kill all the Kalars in Burma or banish them otherwise Buddhism will cease to exist".

The 'other'

Treatment of Muslims as the 'other' persists despite the country's push to embrace the outside world and everything it offers. There is something of a contradiction then in the population's desire to become global players, which will see it interacting far more with non-Myanmar, non-Buddhist ethnicities. In Arakan state, where tension between Buddhists and Muslims often spills over into violence, hypocrisy is also evident in attempts by Arakanese to goad public opinion against the Rohingya in the name of "nationalism". These are the same Arakanese who, ironically, regularly accuse the government of attempting to aggressively assimilate Arakanese into the Burman way of life.

Such is the treatment of Rohingya that up to 300,000 now reside in Bangladesh, which in turn sees them as illegal immigrants from Myanmar and denies them citizenship. They are the epitome of stateless, and spend their lives in unofficial camps where conditions are notoriously poor (only 28,000 are registered by the UN). Their disaffection has made them ripe for Islamic militant groups and human traffickers. Many attempt the perilous sea journey from Bangladesh to Malaysia and beyond to find work - in December last year, a boatload of more than 60 who ran into trouble off the coast of southern Myanmar were detained by Myanmar police, ironically on immigration charges.

Accusations that the government has sought to dilute, or "Burmanise", Myanmar's 135 distinct ethnic groups have existed for decades, and factor in the apparently institutional practice of rape of ethnic women by Myanmar troops, as well as the forced learning of the Myanmar language in ethnic schools.

In Northern Arakan state, where the majority of Rohingya reside, and where foreigners are barred from entering, the practice is effectively official: government policy stipulates that Rohingya babies born out of wedlock be placed on blacklists that bar them from attending school and later marrying. A Rohingya couple must apply well in advance before attempting to wed; the frequent denial by authorities, as well as a strict two-child policy reserved only for Rohingya, has led rights groups to accuse the government of attempting to slowly wipe out the population.

Racism or religious discrimination?

Naypyidaw uses the premise of "illegal migration management" and "control on population growth" to justify the persecution of this group. The "immigrant" label however does not match with evidence that modern-era Muslim political participation in Arakan state goes back to the 1930s, while the Arakanese city of Mrauk U, in its zenith in the 17th century a key trading hub in Asia, was ruled by Muslim sultans.

Nor is this a consistent measure, given the millions of Chinese that have migrated to Myanmar in recent decades to become powerful players in the economy. Is there an issue then with the often darker skin of Muslim groups in Myanmar, or that their religion conflicts with Buddhism?

Few seem to know, but one major cause for concern is that this hostility exists across the entire spectrum of Myanmar politics. The post-colonial civilian government of U Nu in the early 1950s expelled the Burma Muslim Congress and made Buddhism the state religion; then came Myanmar's first dictator, Ne Win, who used anti-Muslim propaganda to powerful effect during the mass expulsion of Indians in the 1960s. He branded the tens of thousands brought in for work by the British as colonial stooges, and exploited the subsequent anti-Islam sentiment to ban all Muslims from the army. The same key issue that fuelled the infamous anti-Chinese riots of the late 1960s and 1970s - that Myanmar were aggrieved at jobs going to foreigners - had also driven the anti-Indian and anti-Muslim riots in 1930 and 1938.

Ne Win's propaganda may have had a lingering effect, given the marked levels of resentment and suspicion of Muslims that remain, particularly in the west of the country. Nicholas Farrelly, a Southeast Asia specialist at the Australia National University, thinks however that this is consistent with the attitudes that many Buddhists elsewhere in the region have towards Muslims:

"In general, they find their habits foreign, their lack of integration exasperating, and their proselytising unwelcome. When we compare them to other groups, Myanmar's Muslims enjoy none of the educational or international prestige that is widely associated with the country's Christian minorities. While Kachin and Karen Christians have suffered atrocious treatment I think there is at least some mainstream Myanmar Buddhist respect for their cultures and religion. Such respect is rarely accorded to Muslims."

An 'open', but racist, Myanmar?

In an era of cautious opening, the continued inability of Myanma to debate the subject rationally is worrying. The opposition National League for Democracy, viewed by the outside world as the driving force for change in Myanmar, itself tiptoes around the subject - one party official told the BBC earlier this year that "even in our organisation the Rohingya question has not been settled". Ko Ko Gyi, a prominent pro-democracy activist, said last week that the Rohingya "are not a Myanmar ethnic race... It has become a national concern infringing on our sovereignty". Does he also think that Thailand, for example, should hold the same attitude towards the hundreds of thousands of refugees from Burma living on its soil?

Aung San Suu Kyi, who has been criticised for failing to properly address the wider "ethnic issue" in Myanmar, urged the Buddhist majority to "have sympathy for minorities" in the wake of the June 3 killings, but refuses to weigh in heavily on the debate. She justified this tentativeness by saying that her party "must cautiously avoid amplifying the situation" - that may be true, but what could also be at stake is the risk of losing support from Arakan state's Buddhist population.

Even among the revered monastic community, often seen as staunch defenders of equality in Myanmar, there has been controversy. The Democratic Voice of Burma reported on a statement released by influential monk and former political prisoner, Ashin Virathu, that said: "I see that Muslims make up a larger percentage of the perpetrators in rape and murder cases". It was "reasonable", he continued, that the "[rape] victim's side see this as an insult to their people and [Buddhist] religion".

Now, despite the government announcing an investigation into the killings, race riots have erupted in western Myanmar and President Thein Sein on Sunday announced a state of emergency. At least eight people have been killed, some allegedly by government troops who opened fire on crowds.

Below the surface

The marked difference between now and past periods of heightened racial tension however is that there has been no major influx of Muslims in recent years - perhaps this points to a tension within Myanmar society that has simmered for years, unaddressed and awaiting a trigger.

One hopes this grisly period will bring about some thorough and measured questioning of the catalysts behind the massacre and resultant crisis, but the often inflammatory nature of these discussions induces avoidance. Few therefore acknowledge that xenophobia and fear of "the other" exists in Myanmar, meaning it goes unchallenged.

A census is due to take place in 2014 - the first in 25 years - but at present around 800,000 Rohingya are unlikely to be included. Such discriminatory policies are a major blight on Myanmar's revamped international image, but are largely obscured by the taboo that surrounds exposure of it - observers are loath to broach the subject, given the ramifications that accompany accusations of racism.

But evidence of an ingrained hostility among civilians is there, and it needs to be recognised. The massacre is not the first such sign - a BBC report last year that carried a map depicting Arakan state as the home of the Rohingya sparked an alarming uproar, and online forums again became hubs of bitter discussions, including calls for a nationwide boycott of the BBC and demonstrations outside the British embassy in Yangon.

If Myanmar is to truly join the global community, the floor must be opened to debate. There must be acknowledgement that a malaise exists among the very Myanma that for decades have felt the pain of antipathy and isolation. Taking a sensitive but head-on approach to the problem, rather than the pussyfooting demonstrated even by powerful figures in the pro-democracy movement, would be the first step.

Francis Wade is a freelance journalist and analyst covering Myanmar and Southeast Asia.

Follow him on Twitter: @Francis_Wade