Myanmar's navy seized a boat packed with 727 people off the country's southern coast on Friday, the government said, about a week after it found a similar vessel it said carried around 200 Bangladeshi migrants.
Most of those on board this boat were also from Bangladesh, a senior official from the president's office, Zaw Htay, told Reuters.
Earlier, Myanmar's Ministry of Information described them as "Bengalis", using the term the government uses to describe the country's persecuted Muslim Rohingya minority as well as people from Bangladesh.
Myanmar insisted it was not to blame for Southeast Asia's latest influx of "boat people" at a regional crisis meeting in Thailand on Friday, as the United States said thousands of vulnerable migrants remained adrift at sea and needed urgent rescue.
More than 4,000 migrants have landed in Indonesia, Malaysia, Thailand, Myanmar and Bangladesh since Thailand launched a crackdown on human trafficking gangs this month. About 2,000 are believed to be still adrift.
Pictures posted on the Myanmar Ministry of Information's Facebook page showed scores of men huddling shoulder-to-shoulder under the sun on the front deck, while uniformed officials - one of them carrying a rifle - stood above. Women could be seen crammed together in the boat's cabins.
The navy found the boat 30 nautical miles off Myanmar's southern coast in the Andaman Sea. The government said there were 608 men, 74 women and 45 children on board.
Myanmar's Ministry of Information's Facebook page Source: Facebook
The ministry later said that authorities found after questioning those on board that they had been at sea since March and at least 50 of them had died in that time. They set off on three boats and had waited in Thai territorial waters since April to be picked up by traffickers who would take them to Malaysia, but when no one turned up, they came back.
The 11 crew members, identifed as Thai nationals, then crammed the migrants on one boat and left on the other two vessels, the ministry said in a statement on its website.
"Arrangements will be made to repatriate the people found on the boat to their country after necessary investigation," it added.
