More than 500 people, most of them Rohingya refugees, are feared dead after two boats capsized off the coast of Myanmar in recent weeks, according to a joint statement issued on Thursday by the UN refugee agency (UNHCR) and the International Organization for Migration (IOM). The vessels departed from Myanmar’s western Rakhine State in late June, carrying mostly Rohingya passengers, some of whom had travelled from the sprawling refugee camps in Cox’s Bazar, Bangladesh.

One boat, believed to have been carrying around 250 people, lost contact shortly after setting sail. A second vessel, reportedly with about 280 people on board, is thought to have sunk off Myanmar’s Ayeyarwady coast on 8 July. The UN agencies stressed that the incidents and casualty figures have not been officially confirmed, but said they were “gravely concerned by the potentially devastating loss of life”.

The journeys took place outside the regular sailing season, when maritime conditions are typically more hazardous. The statement noted that recent torrential rain and widespread flooding across the region had further increased the risks. If verified, the tragedy would add to the nearly 300 people already reported missing or dead in the Andaman Sea and Bay of Bengal this year, including Rohingya refugees and Bangladeshi nationals.

The UNHCR and IOM called for enhanced search and rescue efforts, access to asylum and protection, and actions against smuggling and trafficking networks. They also urged sustained international support for refugees and host communities, while acknowledging Bangladesh’s “remarkable generosity” in sheltering Rohingya for years. The circumstances of both sinkings remain under investigation, and no official death toll has been released.