The Bangladeshi government has relocated more than 3,000 Rohingya to a remote island in the Bay of Bengal, despite concerns from rights groups that many of the persecuted refugees might have been coerced into moving to the flood-prone island.

At least 1,800 refugees were shipped to the Bhashan Char island on Tuesday, weeks after the first batch of 1,600 Rohingya were transferred. The government plans to eventually move 100,000 Rohingya to the remote island as it aims to decongest refugee camps in Cox’s Bazar, which shelter approximately one million Rohingya.

The United Nations and rights groups have condemned the relocation to the island, which is prone to cyclones and flooding.

Refugees and humanitarian workers say some of the Rohingya were coerced into going to the island, which emerged from the sea only 20 years ago.

More than 700,000 Rohingya took shelter in the camps in Bangladesh in 2017 after a deadly clampdown by Myanmar’s military that the UN has said could be genocide.

Several attempts at repatriation of the Rohingya to Myanmar have failed after the refugees said they were too fearful of further violence to return.