Relatives of some 180 Rohingya refugees who had been drifting for several weeks in the Indian Ocean have lost contact with the damaged boat and consider them "dead", according to the UN High Commissioner for Refugees (UNHCR).
Thousands of Rohingyas, a persecuted Muslim minority in Burma, try every year to leave the refugee camps in Bangladesh to reach Malaysia or Indonesia by sea during very perilous crossings.
The boat, with dozens of women and children on board, is believed to have departed last month and was reported in poor condition off the coasts of Thailand, India, then Malaysia and Indonesia.
“Relatives have lost contact. Those who were able to contact them last consider that they are all dead. We hope this is not the case,” UNHCR tweeted this weekend.
“If true, this is dramatic news. Our thoughts are with the families who would have lost loved ones in this shocking tragedy. We repeat our calls to countries to save lives. This must be the priority,” he added.
A 23-year-old young woman, Munuwara Begum, who had boarded this boat, came into contact last week with her family who live in a large camp for Rohingya refugees in Bangladesh.
“We are in danger. Help us”, had launched the young woman, according to an audio recording of the call.
"We have no water or food, and no one to save us from this sinking boat."
On Sunday, another wooden boat with a broken engine, the third in two months, arrived in western Indonesia with 57 Rohingya refugees, all men, after a month at sea, local police said.
In December, 104 Rohingya refugees were also rescued off Sri Lanka after crossing the Bay of Bengal, according to media reports.
The UN's International Organization for Migration (IOM) called on countries in the region "to work together urgently to avoid a repeat of the 2015 crisis" when thousands of Rohingya refugees fled by boat, with heavy loss of life off Malaysia, Indonesia and Thailand.
"Governments and their partners have successfully worked together before to find regional solutions [...] we again call for urgent regional action."