Bangladesh said it will start repatriating refugees from an initial group of 2,260 from today despite warnings the Rohingya face almost certain persecution in Myanmar, AFP reported.
Many of the million refugees in the teeming camps have expressed terror at the prospect of returning to Myanmar, where UN investigators say they were targeted in a military campaign that amounted to genocide.
Bangladesh said only those who volunteer will be returned, but the UN rights chief said many refugees are panicking at the prospect of being sent back against their will.
Some families listed to return have fled, community leaders and refugees have told AFP, hiding in the hills where more than 720,000 Rohingya sought refuge from a Myanmar military crackdown launched from August last year.
They joined some 300,000 Rohingya already living in squalid camps in Bangladesh's southeast for years, having fled previous waves of violence in Rakhine state.
Additional police and soldiers were seen patrolling the camps and checking identity cards, stoking anxiety as the deadline for repatriation looms, refugee leaders told AFP.
Bangladesh officials remain optimistic the large-scale refugee returns will start as planned today.
They plan to send 150 people on the opening day.
UN High Commissioner for Human Rights Michelle Bachelet on Tuesday urged Dhaka to reconsider.
"With an almost complete lack of accountability – indeed with ongoing violations – returning Rohingya refugees to Myanmar at this point effectively means throwing them back into the cycle of human rights violations that this community has been suffering for decades," she said in a statement.
She said the violations against the Rohingya "amount to the worst atrocities, including crimes against humanity and possibly even genocide."
US Vice President Mike Pence told Aung San Suu Kyi the violence against the Rohingya was "without excuse", adding pressure to Myanmar's civilian leader who this week had an Amnesty International honor revoked.