Myanmar on Monday said it has detained several police over a 'selfie-style' video that appears to show officers beating Rohingya civilians, a rare admission that security forces may have carried out abuses against the Muslim minority.
Tens of thousands of people from the persecuted ethnic group -- loathed by many of Myanmar's Buddhist majority -- have fled a military operation in Rakhine state, launched after attacks on police posts in October.
Bangladesh says some 50,000 Rohingya have crossed its border over the past two months. Many have brought harrowing accounts of rape, murder and arson at the hands of Myanmar's security forces.
Their stories have raised global alarm and galvanised protests against Myanmar's de facto leader, Aung San Suu Kyi, who has been accused of not doing enough to help the Rohingya.
Her government has said troops are hunting militants behind the deadly raids on police border posts, denying claims of atrocities with a flurry of public statements.
However, on Monday authorities pledged to take action "against police who allegedly beat villagers during area clearance operations on 5 November in Kotankauk village".
Suu Kyi's office named four officers who were involved in the operation including constable Zaw Myo Htike, who looks nonchalantly into the camera smoking as he records the video.
"Those who (were) initially identified were detained," it said in a statement. "Further investigations are being carried out to expose other police officers who beat villagers in the operation."
Dozens of videos have emerged apparently showing security forces abusing Rohingya, but this is the first time the government has said it will take action over them.
The footage shows police hitting a young boy around the head as he walks to where dozens of villagers are lined up in rows seated on the ground, hands behind their heads.
Three officers in uniform then start attacking one of the sitting men, beating him with a stick and kicking him repeatedly in the face.
A Rohingya activist contacted by AFP said the footage had been verified by a refugee from the nearby camp, Shilkhali.
Around 600 people have been detained since the military operation, according to state media, including six who died in police custody in largely unexplained circumstances.
"Unfortunately the scene this video depicts isn't unique or an isolated event," said Matthew Smith, chief executive of Fortify Rights.
"It's significant the government acknowledged the video, but it remains to be seen what will come of it. Impunity still rules the day in Rakhine state."
Myanmar has long discriminated against the stateless Rohingya, who rights groups say are among the most persecuted peoples in the world.
More than 120,000 have been trapped in squalid displacement camps since violence erupted in 2012 in Rakhine, where they are denied citizenship, access to healthcare and education.
Over a dozen Nobel laureates wrote to the UN Security Council last week urging action to stop the "human tragedy amounting to ethnic cleansing and crimes against humanity" in northern Rakhine.
Under Myanmar's junta-era constitution Suu Kyi's civilian administration has limited power over the army, which maintains control of the defence, home and border ministries.