LANGKAWI - Malaysia on Wednesday joined Indonesia in vowing to turn back vessels ferrying a wave of migrants to Southeast Asian shores, deepening the misery facing boatloads of people who advocates say are at risk of starvation and disease.
Thailand has called for a May 29 regional summit to address what it called an "unprecedented increase" in arrivals of ethnic Rohingya refugees from Myanmar and impoverished Bangladeshi migrants.
Migrant groups are urging regional authorities to act quickly to avert a humanitarian catastrophe, saying a people-smuggling crackdown in Thailand has stranded possibly thousands of men, women and children at sea aboard overcrowded vessels.
But Malaysia said it would turn away boats entering its waters, except if they were in imminent danger of sinking.
"The policy has always been to escort them out of Malaysian waters after giving them the necessary provisions" including fuel, water and food, First Admiral Tan Kok Kwee of the Malaysian Maritime Enforcement Agency told AFP on the resort island of Langkawi.
More than 1,000 exhausted and starving migrants have swum to safety on Langkawi in recent days after being dumped ashore or deserted on their boats by smugglers, with hundreds of others straggling to land in Indonesia.
Indonesia's navy has said it turned away one vessel packed with hundreds of abandoned migrants.
Thailand's disruption of smuggling networks comes after the UN refugee agency reported a surge in migrants leaving Bay of Bengal ports. It said 25,000 had embarked from January to March, double the rate seen in the same period last year.
Bangladeshi authorities said they seized a fishing trawler filled with 116 of its nationals in the Bay of Bengal near Myanmar on Tuesday.
"They have been on the boat from 15 days to three months," coastguard station commander Dickson Chowdhury told AFP.
"For the last seven days some of them have not eaten anything other than water. Some were found in emaciated condition," he said.
Horrific survivor accounts
A group advocating for the rights of Rohingya, a Muslim minority in Myanmar, says as many as 8,000 other people may be adrift.
The Arakan Project also said it had spoken by phone with passengers aboard one vessel carrying 350 people, who said they were abandoned by their Thai smugglers.
"They told us they have had no food and water for the last three days. They have called for urgent rescue," said Chris Lewa, the group's founder.
Thousands of Rohingya people, who are denied citizenship by Buddhist-majority Myanmar, flee annually to escape discrimination and sectarian violence that has targeted them in recent years.
Recent arrivals in Indonesia and Malaysia have recounted horrific tales.
Muhammad Shorif, a 16-year-old Rohingya from Myanmar, fled the squalor of a refugee camp in hopes of reaching relatively prosperous Malaysia.
He said he spent a month aboard a smuggling ship jammed with hundreds of others who survived on meagre rations and faced beatings from armed smugglers.
"Six people on our boat died due to illness and hunger, and the captain ordered that their bodies be thrown to the sea," he told AFP in Indonesia's northern Aceh region.
He and hundreds of others came ashore in Aceh after smugglers left them on the boat to fend for themselves.
The International Organisation for Migration has said search-and-rescue operations are urgently needed to find stricken migrant boats.
"It needs a regional effort... we don't have the capacity to search for them, but governments do," said Joe Lowry, a Bangkok-based spokesman for the IOM.
The inter-governmental group has also demanded a coordinated and sympathetic response by Europe as the continent grapples with its own migration crisis originating in North Africa.
Thailand launched its trafficking crackdown after discovering dozens of migrant corpses in secret jungle camps earlier this month.