"The government is checking their identity, asking what they want to do and where they want to go," government spokesman Ye Htut told Reuters, without providing further details of the boat's location.

"Usually, most of them want to go back to Bangladesh, so we will arrange according to their wishes."

Government officials have been tight-lipped about the identities of 727 migrants on the overcrowded boat, found drifting and taking on water early Friday, as well as their eventual destination.

The government initially labeled the migrants "Bengalis", a term used to refer to both Bangladeshis and Rohingya Muslims, a largely stateless minority in Myanmar that the government refuses to refer to by name. Officials later said they believed most of those on board were from Bangladesh.

Myanmar has come under harsh criticism for its treatment of Rohingya, more than 100,000 of whom have fled persecution and poverty in Rakhine State since 2012. Myanmar denies discriminating against the Rohingya.

A spokeswoman for the U.S. State Department said the United States had asked Myanmar to allow the immediate disembarkation of and provision of humanitarian assistance to the migrants.

"The safety and well-being of these migrants is the highest priority of the international community, including the U.S., which stands ready to provide assistance as needed," Marie Harf told a news conference.

MYANMAR MUST END DISCRIMINATION - OBAMA

U.S. President Barack Obama told young Asians invited to the White House on Monday that Myanmar needed to end discrimination against Rohingya if it wanted to be successful in its transition to a democracy, something he has sought to make a legacy of his presidency.

"(O)ne of the most important things is to put an end to discrimination against people because of what they look like or what their faith is," he said. "And the Rohingya have been discriminated against. And that’s part of the reason they’re fleeing."

Journalists from Reuters and other foreign media were briefly detained and turned back to land after approaching the fishing boat on Sunday.

Navy officials made journalists delete photographs and video of the boat and at one stage a sailor pointed a rifle at reporters.

A navy officer, who declined to be named, told Reuters on Sunday some migrants aboard were able to speak Rakhine, a local language in the western state not widely spoken in Bangladesh.

Myanmar says the Rohingya are illegal migrants from neighboring Bangladesh, and denied during a 17-nation meeting on the crisis in Bangkok last week that it was to blame for a crisis that has seen more than 4,000 Rohingya and Bangladeshi "boat people" arrive across Southeast Asia in recent weeks.

The migrants were abandoned at sea by people smugglers after Thailand launched a crackdown on trafficking in early May.

"Just days after the Bangkok summit on the boat people and the Myanmar authorities are already shamefully violating what was agreed there," Phil Robertson, deputy director of Human Rights Watch's Asia division, told Reuters.

Myanmar should immediately grant access to the migrants to international agencies, Robertson said, "especially since no one in the international community believes (its) rash and rushed assessment that these people are all from Bangladesh".

Kasita Rochanakorn, a spokeswoman for the United Nations High Commissioner for Refugees in Yangon, said UNHCR had previously been invited to help refugees at a disembarkation point in southern Myanmar, but had been "subsequently told that the place of disembarkation had been changed".

The UNHCR was still waiting for more information on where the migrants would be unloaded, she said.

Myanmar officials had said last month that another migrant boat found at sea with more than 200 people on board was mostly filled with Bangladeshis.

But interviews by Reuters found more than 150 Rohingya had earlier been on the same boat, but were quietly whisked off by traffickers before authorities brought the boat to shore.

Last Thursday, U.N. human rights chief Zeid Ra'ad Al Hussein painted a "grim picture of discrimination against Rohingya" at a closed-door briefing at the U.N. Security Council, a council diplomat said.

U.S. Ambassador to the United Nations Samantha Power called the conditions the Rohingya faced "troubling and inhumane."