The relatives of around 180 Rohingya refugees who have been floating on a boat in the Indian Ocean for weeks assume their deaths.
"The relatives have lost contact.
We hope (...) that this is not the case, "said the UN refugee agency UNHCR on Twitter on Sunday and expressed its condolences to the families.
“We reiterate our appeals to states in the region to save lives.
This has to be a priority.”
Thousands of the Rohingya minority, who are mostly Muslim and persecuted in Myanmar, make risky crossings from Myanmar or the refugee camps in Bangladesh to reach Malaysia or Indonesia.
The latest boat, carrying around 180 passengers, is said to have sailed last month and was reportedly adrift near Thailand, Malaysia, Indonesia, the Indian Andaman Islands and the Strait of Malacca - one of the busiest shipping routes in the world.
Last week, a resident of a refugee camp in Bangladesh said she spoke to her 23-year-old sister Munuwara Begum, who was on the boat, via walkie-talkie.
“We are in danger.
Please save us," Begum said.
There is neither food nor water on the boat and there is no rescue in sight.
On Sunday, another refugee boat with a broken engine and nearly 60 Rohingya on board landed on Indonesia's west coast after a month at sea, according to police.
More than 100 Rohingya refugees were reportedly rescued last week by another boat off Sri Lanka - hundreds of kilometers from Myanmar on the other side of the Bay of Bengal.