NEW DELHI — Since August last year, more than half a million Rohingya have undertaken perilous journeys to Bangladesh to flee persecution and violence in Burma. Now, the first Rohingya family has returned to Rakhine, Burma’s government said in a Facebook post late Saturday, a statement that Bangladesh’s government and the United Nations have challenged.

An estimated 687,000 Rohingya — about half of Burma's entire population of Rohingya, a stateless Muslim ethnic minority group — have left their homes in northern Rakhine state since violence erupted in August, crossing into Bangladesh and settling in vast and squalid refugee camps. Those who fled said they left because of widespread rape, arson and killings. The U.S. government and the United Nations describe the violence against the Rohingya as “ethnic cleansing.”

Burma has strongly denied that allegation — saying the army waged a legitimate operation against insurgent Rohingya militants who had attacked more than two dozen police posts and an army base in August.

The Rohingya exodus has created a humanitarian crisis in Bangladesh, a small, poor country that is one of the most densely populated in the world.

In an effort to address the crisis, Bangladesh and Burma signed a deal in November to repatriate the Rohingya over the course of two years, beginning in January.

The Facebook post on the official page of Burma’s Information Committee appears to show a family of five getting health checks and receiving packages of rice, mosquito netting and blankets. “The five members of a family ... came back to Taungpyoletwei town repatriation camp in Rakhine state this morning,” the post said.

The pictures also show the family — one man, two women and a young girl and boy — receiving national verification cards, which Rohingya activists have rejected, saying they are a way to deny Rohingya people citizenship.

Bangladesh’s Refugee Relief and Repatriation Commissioner, Abul Kalam, said Bangladesh had no involvement in the repatriation.“This is in no way a repatriation, rather it is propaganda,” he told Reuters.

The U.N. High Commissioner for Refugees (UNHCR) also separately issued a statement saying it had no knowledge of this case and was not consulted or involved in this reported return.

Zaw Htay, a spokesman for the Myanmar government said “this is not propaganda,” and that the family decided to come back of their own volition. “We are taking care of them,” he told Reuters.

Although the Rohingya have lived in Burma for many generations, most Burmese consider them unwanted immigrants from neighboring Bangladesh and refer to them as “Bengalis,” a term the Rohingya consider derogatory.

The United Nations has warned that a mass repatriation of Rohingya would be premature. The Office of the U.N. High Commissioner for Refugees said Friday that “conditions in Myanmar are not yet conducive for returns to be safe, dignified, and sustainable.”

Waves of violence have forced Rohingya out of Burma during the past several years, with more than 200,000 Rohingya refugees already in Bangladesh before last year’s exodus. Many refuse to return without a guarantee of basic rights and citizenship.

Rohingya who have been repatriated in the past have been forced to live in camps in Burma.

Meanwhile, boats carrying Rohingya from Rakhine state continue to leave Burma. The most recent one, carrying 70 Rohingya, reportedly set out from Burma toward Malaysia on Thursday, the same day the family of five returned to Rakhine