Thailand's prime minister has admitted that some Rohingya migrants have been pushed back out to sea after they were intercepted by Thai authorities.
In an interview with CNN Abhisit Vejjajiva said he believed there were "some instances" in which boatloads of migrants arriving on Thai shores were pushed back, but he was not clear who had approved the practice.
"All the authorities say it's not their policy, but I have reason to believe some instances of this happened," he told the US news network.
"If I can have the evidence as to who exactly did this I will certainly bring them to account."
Thailand has faced international condemnation following statements from Rohingya migrants claiming abuse at the hands of Thai authorities before being set adrift far out to sea.
Abhisit did not make any comment on the claims of severe beatings many migrants said they had received from the Thai military.
Human rights groups have accused the Thai armed forces of running a systematic campaign of abuse against Rohingya migrants, forcing them back to sea in boats without engines.
The Rohingya are a Muslim ethnic group from north-eastern Myanmar.
They are not recognised as citizens by Myanmar's military government, and many complain of brutal treatment at the hands of Myanmar authorities.