As relocations began, hundreds of Rohingya refugees were seen boarding buses in front of refugee camps in Cox's Bazar, a coastal town near the Bangladesh-Myanmar border.

They were heavily guarded by security forces and barred from talking to journalists. Government officials, who were present at the site, have yet to give any official statement. Additional police forces were seen patrolling the area.

The refugees are being taken to Bhashan Char, which formed out of Himalayan silt flowing into the Meghna Estuary in the Bay of Bengal less than 20 years ago. Located 34 kilometers (21 miles) from mainland Bangladesh, Bhashan Char's geography makes it prone to cyclones and floods — its name in Bengali means "floating island."

Read more: Does Myanmar soldiers' murder confession prove Rohingya genocide?

The island used to be regularly submerged by monsoon rains, but the Bangladeshi navy has spent over $112 million (€92 million) to build flood protection, along with barracks, hospitals and mosques.

The government built these facilities with plans to accommodate 100,000 Rohingya refugees. However, this is just a fraction of the estimated 1 million who have fled violent persecution in their native Myanmar and are currently living in crowded, squalid refugee camps in Cox's Bazar.

UN 'not involved' in relocation

International aid agencies and the United Nations have vehemently opposed the relocation since it was first proposed in 2015. They fear a big storm could overwhelm the island and endanger thousands of lives. However, Bangladesh has said the necessity of easing overcrowding in Cox's Bazar outweighs these concerns.

Just before the relocations started on Thursday, the UN released a statement saying it was "not involved" in the process and had "limited information."

Read more: Myanmar and UN sign deal on steps for Rohingya return

"The UN has also consistently maintained that any relocations to Bhashan Char should be preceded by comprehensive technical protection assessments," the statement continued.

"These independent UN assessments would review the safety, feasibility, and sustainability of the island as a place for refugees to live, as well as the framework for protection and the assistance and services they would be able to access on the island," it added.

The UN has also voiced concern over whether the Rohingya have been allowed to make a "free and informed decision" about relocating to the island.

Are refugees forced to move?

Although Bangladesh's government has repeated that relocations will be entirely voluntary and no refugee will be forced, rights groups have said they have evidence to the contrary.

Both Amnesty International and Human Rights Watch (HRW) have published statements from Rohingya who claim to have been forced or lured into relocating to the island.

The refugees who agreed to move were reportedly promised that they would receive priority to go back to Myanmar if repatriation takes place, or alternatively get priority resettlement in third countries.

Read more: Saudi Arabia pressures Bangladesh to issue passports to Rohingya

Other incentives reportedly included access to education, and cash, along with threats of consequences if they refused relocation.

"They beat my son mercilessly and even smashed his teeth so that he agreed to go to the island," Sufia Khatun, a 60-year-old refugee, told the Agence France-Presse news agency, while seeing off her son and five relatives Thursday at the transit camp.

"I have come here to see him and his family probably for the last time," she added.

"My brother has been missing for the last two days. We later learned that he is here, from where he will be taken to the island. He is not going willingly," Hafez Ahmed, another refugee, told AFP.

Nay San Lwin, co-founder of Free Rohingya Coalition, thinks the relocation process was not as transparent as had been promised by the government. He said some refugees even fled from the camps to avoid relocation.

"Some refugees complained that they were coerced into registering for relocation. Others were surprised to see their names on the list of those willing to go to the island as it had not been discussed with them before," he told DW.

"As I understood, the authorities have a list of refugees who are to be relocated. However, it's not clear how the list was made," Lwin added.

Read more: The voice of the Rohingya refugees

Bangladesh's unilateral relocation

As Bangladesh starts the relocation process, there is growing international pressure on Myanmar over the alleged persecution by its military of the Rohingya in the northeastern Rakhine state.

The Buddhist-majority country currently faces two separate lawsuits, one at the International Criminal Court and another at the International Court of Justice, for a 2017 military campaign that drove many Rohingya across the border into Bangladesh.

Experts told DW that Bangladesh's unilateral decision to relocate the refugees could shift international attention away from efforts to send them back to Myanmar.

Read more: Myanmar's Rohingya: A history of forced exoduses

"The Bangladesh government is actively reneging on its promise to the UN not to relocate any refugees to Bhashan Char island until humanitarian experts give a green light," said Brad Adams, Asia director at HRW.

"If the government was genuinely confident in the habitability of the island, they would be transparent and not hastily circumvent UN technical assessments," he said.

Aid groups say they should take part

C.R. Abrar, chief coordinator for the Refugee and Migratory Movements Research Unit (RMMRU), a Bangladeshi NGO working on Rohingya issues, said Bangladesh's move has diverted the attention of international human rights groups from repatriation to relocation.

"Bangladesh has put more pressure on its back," Abrar told DW, adding that despite Bangladesh's generosity in providing shelter for over 1 million refugees, international donors have spent hundreds of millions of euros to feed them.

"Ignoring international donors' concerns in the relocation process could have a negative impact on the overall situation," Abrar said. "Bangladesh could have avoided it by involving the UN and other agencies."

Read more: Germany pledges €15 million to Rohingya cause

Human rights expert Brad Adams urged donor countries to take a stand in ensuring transparency in the relocation process.

"Donor governments engaged in the Rohingya crisis response, such as the US, UK, Japan, Australia and Canada, should take a clear stand against this rash move to relocate Rohingya to Bhashan Char," he said.

"Decisions to move after the completion of technical assessments need to be voluntary and fully informed," he added.

Saad Hammadi, Amnesty International's South Asia campaigner, echoed a similar opinion.

"The German government must prioritize human rights of the Rohingya people in its humanitarian response, and ensure that they have full and meaningful participation in the decisions that affect them," he told DW.

The Bangladeshi government did not respond to DW's requests for comment.