In recent months, tens of thousands of Rohingya have fled to Bangladesh amid a military crackdown on insurgents in Myanmar's western Rakhine state.
They have told horrifying stories of rapes, killings and house burnings, which the government of Myanmar - formerly Burma - has claimed are "false" and "distorted".
Activists have condemned the lack of a firm international response. Some have described the situation as South East Asia's Srebrenica, referring to the July 1995 massacre of more than 8,000 Bosnian Muslims who were meant to be under UN protection - a dark stain on Europe's human rights record.
Tun Khin, from the Burmese Rohingya Organisation UK, says Rohingyas are suffering "mass atrocities" perpetrated by security forces in the northern part of Rakhine state.
A counter-insurgency campaign was launched after nine border policemen near Maungdaw were killed in a militant attack in early October, but the Rohingya say they are being targeted indiscriminately.
The BBC cannot visit the locked-down area to verify the claims and the Myanmar government has vociferously denied alleged abuses.
But UN officials have told the BBC that the Rohingya are being collectively punished for militant attacks, with the ultimate goal being ethnic cleansing.
What led to the current situation?
The Rohingya are one of Myanmar's many ethnic minorities and say they are descendants of Arab traders and other groups who have been in the region for generations.
But Myanmar's government denies them citizenship and sees them as illegal immigrants from Bangladesh - a common attitude among many Burmese.
The predominantly Buddhist country has a long history of communal mistrust, which was allowed to simmer, and was at times exploited, under decades of military rule.