The UN's refugee agency on Friday called for the Thai government to probe reports its sailors shot at Rohingya boat people fleeing sectarian strife in Myanmar.
Citing survivors of the alleged shooting in late February, the UNHCR said at least three shots were fired by Thai sailors as they intercepted a Rohingya boat off Phang Nga, southern Thailand, and towed it further out to sea.
But it was unclear "whether these were warning shots or aimed at the passengers," it said in a statement, adding the boat had been at sea for three weeks and was low on supplies since leaving Myanmar's unrest-hit Rakhine State.
The survivors were among a group of 121 Rohingya who spoke to the UNHCR after arriving in Aceh, Indonesia on February 26.
"Survivors and local fishermen near Phuket said two dead bodies were recovered from the sea, though it was unclear if the cause of death was shooting or drowning," it said, repeating a toll reported earlier by rights groups.
The UN said the boat was twice towed back out to sea to prevent the Rohingya from landing on Thai soil, adding it was "gravely concerned" by the tactic of turning away "people fleeing unrest".
Speaking to AFP from a detention centre in Aceh, Indonesia in late February a Rohingya asylum seeker said boats were stopped in Thai waters and then taken further out to sea -- although it's not clear if he was referring to the same boat as the UN.
Thailand's foreign ministry has refuted the accusations, insisting there is "no reason to shoot or hurt" Rohingya.
The UN describe Rohingya as among the most persecuted minority groups in the world. Myanmar views its population of roughly 800,000 as illegal Bangladeshi immigrants and denies them citizenship.
Buddhist-Muslim unrest in the western Myanmar state of Rakhine has left at least 180 people dead and more than 110,000 displaced since June 2012.