An estimated 582,000 people have fled to Bangladesh since late August
Amnesty International claims there has been a campaign of "crimes against humanity" against Rohingya Muslims in Myanmar, also known as Burma.
Burmese police and army launched a violent crackdown in the northern Rakhine state following attacks by Rohingya insurgents on police posts in August.
It is believed that thousands of people in the state have been killed or tortured by security forces.
According to the UN, an estimated 582,000 Rohingya Muslims have fled to Bangladesh since late August to escape the violence.
Amnesty says it has spoken to dozens of people who have witnessed the violence, saying that security forces have carried out a "targeted campaign of widespread and systematic murder, rape and burning".
The human rights charity says it has documented 'at least six' of the International Criminal Court's crimes against humanity in Myanmar - including murder, rape & other sexual voices, deportation & forcible displacement, and torture.
The organisation spoke to 17 survivors of a massacre in the village of Chut Pyin, where 'at least scores' of men, women and children were killed by security forces.
Almost all of the survivors indicated they had lost at least one family member, with some having lost many. Six of he survivors had gunshot wounds.
Amnesty said: "[The survivors] consistently described the Myanmar military, joined by Border Guard Police and local vigilantes, surrounding Chut Pyin, opening fire on those fleeing, and then systematically burning Rohingya houses and buildings."
Colm O'Gorman of Amnesty International Ireland observed: "In this orchestrated campaign, Myanmar’s security forces have brutally meted out revenge on the entire Rohingya population of northern Rakhine State, in an apparent attempt to permanently drive them out of the country. These atrocities continue to fuel the region’s worst refugee crisis in decades.
"Exposing these heinous crimes is the first step on the long road to justice. Those responsible must be held to account; Myanmar’s military can’t simply sweep serious violations under the carpet by announcing another sham internal investigation."
He said that the country's commander-in-chief - Senior General Min Aung Hlaing - must take 'immediate action' to stop security forces committing atrocities.
Report author Matt Weld says satellite imagery indicates a campaign of ethnic cleansing:
Last week, Myanmar's de facto leader Aung San Suu Kyi - who has faced international criticism for her handling of the crisis - announced that an agency would be set up to help resettle the Rohingya Muslims in Rakhine state.