10 a.m. (0300 GMT)

The U.N. refugee agency is estimating that over 3,000 Rohingya and Bangladeshi migrants — or even more — could still be adrift in the Andaman Sea.

The exact numbers are not known, but the U.N. High Commissioner for Refugees says it triangulated reports in the media and other sources and estimates the current number could be over 3,000 — or more that no one knows about.

More than 3,000 Rohingya minority Muslims fleeing persecution in Myanmar and Bangladeshi economic migrants also on the boats with them have already landed in Indonesia and Malaysia, and over 100 in Thailand.

Only Rohingyas are being given a one-year temporary shelter while Bangladeshis face repatriation.

Malaysian navy chief Abdul Aziz Jaafar says four vessels are searching for any migrant ships that could still be out at sea, and three helicopters and three combat boats are on standby.

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3 p.m. (2200 GMT)

The U.S. military says it is preparing to help countries in the region address the humanitarian crisis of the Rohingya migrants stranded at sea.

Pentagon spokesman Lt. Col. Jeffrey Pool told The Associated Press Thursday that the Department of Defense "is responding to this crisis and taking this seriously. We are preparing to stand up maritime aviation patrols throughout the region and working with local partners to help with this issue."

It was the first indication that the U.S. military is ready to take direct role. Washington has been urging governments in the region to work together to conduct search and rescue and provide shelter to thousands of vulnerable migrants.

— Martha Mendoza, Santa Cruz, California

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10 a.m. (1400 GMT)

A bipartisan group of 23 U.S. lawmakers is urging the Obama administration to prevent Southeast Asian seas from becoming a "graveyard" for thousands of Rohingya boat people.

The lawmakers made the appeal in a letter to U.S. Secretary of State John Kerry late Wednesday, ahead of discussions on the crisis between Myanmar's government and the No. 2 ranking U.S. diplomat, Anthony Blinken, in Naypyitaw, Myanmar's capital.

The members of the House of Representatives said the United States should provide support in search and rescue and humanitarian assistance for migrants in imminent danger in the Andaman Sea after fleeing "systematic repression" in Myanmar.

The U.S. should also work with Southeast Asian nations and address the "root cause" of the crisis, it says. The letter is strongly critical of President Thein Sein's government for pursuing "hate-filled" legislation against minorities in Myanmar. It recommends targeted U.S. sanctions against those who incite violence against the Rohingya if the situation continues to deteriorate.

The top-ranking Republican and Democrat on the House of Representatives Foreign Affairs Committee are among the signatories of the letter, which was provided Thursday to The Associated Press. Lawmakers provide oversight, but don't set U.S. foreign policy.

— Matthew Pennington, Washington

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7 p.m. (1200 GMT)

A top U.S. diplomat has urged Myanmar's government to work with its regional partners to address the migrant crisis in Southeast Asia.

Deputy Secretary of State Anthony Blinken met with Myanmar officials in the capital, Naypyitaw, on Thursday.

More than 3,000 people have landed in Indonesia, Malaysia and Thailand in recent weeks, most of them members of the Rohingya minority who were fleeing Myanmar or were tricked by traffickers and then abandoned at sea.

The embassy in Yangon posted on Facebook that Blinken shared the U.S. government's concerns about the migrant crisis. State Department officials in Washington said earlier that the U.S. was willing to lead multicountry efforts organized by the U.N. refugee agency to resettle the most vulnerable migrants.

Blinken said earlier on his trip to Southeast Asia that the only sustainable solution to the problem was addressing the conditions that led the Rohingya to flee.

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4 p.m. (0930 GMT)

The Myanmar government says it will attend a regional meeting on the Rohingya humanitarian crisis next week.

Earlier, Myanmar hinted it might skip the May 29 meeting in Bangkok in neighboring Thailand , which will bring together more than a dozen governments from Southeast Asia and beyond. They want to discuss the root causes of the exodus of Rohingya Muslims from Myanmar as well as Bangladeshi migrants, thousands of whom have been stranded at sea.

More than 3,000 boat people have landed in Indonesia, Malaysia and Thailand in recent weeks, and thousands more are believed to be adrift and their lives in danger.

Myanmar's presidential office director, Zaw Htay, said Thursday that his government will take part in talks about human smuggling and illegal migration.

For decades, the Rohingya have suffered from state-sanctioned discrimination in majority-Buddhist Myanmar. Denied citizenship by national law, they are effectively stateless. In the last three years, attacks on Rohingya have left hundreds dead.

— Robin McDowell, Yangon, Myanmar