While the United States has suspended sanctions against Myanmar, they remain on the books, and Mr. Rhodes noted that two weeks ago the Treasury Department blacklisted a senior Burmese political figure with ties to the military who it said was impeding change.

Derek J. Mitchell, the American ambassador to Myanmar, said: “We need to be smartly and carefully engaged to promote change from the inside. We have no illusions about the challenges.”

American officials are applying the most intense pressure over Myanmar’s treatment of the Rohingya Muslims, which many in the majority Buddhist population regard as interlopers from Bangladesh. Since sectarian rioting two years ago left more than 150 dead, tens of thousands have been herded into internment camps, where the authorities demand that they identify themselves as Bengalis, often beating them if they refuse.

As a measure of the deep discrimination that the Muslim minority faces, Burmese officials on Thursday repeated their position that members of the minority had no right to call themselves Rohingya and called on the outside world to use the term Bengali.

The Burmese government expressed “deep disappointment” that the secretary general of the United Nations, Ban Ki-moon, had used the term Rohingya during a news briefing, saying it would “inflame local sentiment.” Mr. Obama used the word freely in his meeting with Mr. Thein Sein, a senior American official said.

The bias against the Rohingya is so broad in Myanmar that even Ms. Aung San Suu Kyi, a Nobel laureate and human-rights hero, has declined to speak up in their defense. Officials said the subject was likely to come up in Mr. Obama’s meeting with her on Friday, which will be held at her lakeside residence in Yangon, once known as Rangoon.

“We believe that all leaders across the political spectrum can play a role,” Mr. Rhodes said. “Her voice is obviously critically important.”