Five Bangladesh navy ships carrying over 1,700 Rohingya refugees left the southeastern port city of Chittagong on Tuesday for an isolated, flood-prone island where they will be relocated despite concerns among human rights groups about their safety.

The refugees were expected to reach Bhashan Char island after a three-hour naval journey, a government official involved with the process said. The official, who spoke on condition of anonymity because he was not authorised to talk to the media, said the refugees were taken to Chittagong from their camps in Cox's Bazar by buses on Monday and stayed overnight in a temporary camp.