In a Changing Myanmar, Vows of Support From a Visiting President Soe Zeya Tun/Reuters President Obama in Yangon, Myanmar, with the opposition leader Daw Aung San Suu Kyi on Monday. YANGON, Myanmar - President Obama journeyed to this storied tropical outpost of jade and jungles on Monday to "extend the hand of friendship" as a land long tormented by repression and poverty begins to throw off military rule and emerge from decades of isolation. Mr. Obama arrived here as the first sitting American president to visit Myanmar with the hope of solidifying the stunning changes that have transformed this Southeast Asian country and encouraging additional progress toward a more democratic system. With the promise of more financial assistance, Mr. Obama vowed to "support you every step of the way." The president was greeted on a mild, muggy day by tens of thousands of people lining the road from the airport - and by further promises of reform by the government, which announced a series of specific commitments regarding the release of political prisoners and the end of ethnic violence. Although Mr. Obama stayed just six hours, his visit was seen here as a validation of a new era. He met at the government headquarters with President Thein Sein, who has ushered in change, and then made a personal pilgrimage to the home of the opposition leader Daw Aung San Suu Kyi, where she was confined for most of two decades before her release from house arrest two years ago. Overlooking the manicured lawn and well-tended garden outside the elegant two-story lakeside house, the president celebrated the Nobel-winning dissident as an "icon of democracy" who inspired the world, then kissed and embraced her. Still, Ms. Aung San Suu Kyi, who according to human rights activists privately counseled Americans against Mr. Obama's making the trip out of concern that it was premature, sounded a note of caution. "The most difficult time in any transition is when we think that success is in sight," she warned. Then we have to be very careful that we are not lured by a mirage of success. While local leaders attribute the changes so far to internal factors and decisions far removed from policies set in Washington, Mr. Obama was eager to claim a measure of credit and drank in the adulation of the crowd. Outside the gates of Ms. Aung San Suu Kyi's home, thousands of people gathered, chanting, "Obama, Obama!" and crowding his motorcade as it passed. Mr. Obama has tried to play nursemaid to the opening of Myanmar, formerly and still known by many as Burma, by sending the first American ambassador in 22 years, easing sanctions and meeting with Ms. Aung San Suu Kyi at the White House. On Monday, he announced the return of the United States Agency for International Development along with $170 million for projects over the next two years. In a small gesture during his meeting with Mr. Thein Sein, Mr. Obama even called the country Myanmar, the term favored by the generals who renamed it, even though the United States government officially prefers Burma. The president noted that in his inaugural address in 2009 he had vowed to reach out to those "willing to unclench your fist" and hailed Myanmar for responding. "So today, I have come to keep my promise and extend the hand of friendship," Mr. Obama said in a speech at the University of Yangon. He promised to "help rebuild an economy" and develop new institutions that can be sustained. "The flickers of progress that we have seen must not be extinguished - they must be strengthened, they must become a shining north star for all this nation's people," he said. Although human rights activists criticized him for visiting while hundreds of political prisoners remain locked up and violence rages through parts of the country, Mr. Obama used the occasion to nudge Myanmar to move further. He noted that democracy is about constraints on power, pointing to his own limits as president. "That is how you must reach for the future you deserve, a future where a single prisoner of conscience is one too many," he said at the university. You need to reach for a future where the law is stronger than any single leader.