Yangon, Myanmar (CNN) -- U.S. Secretary of State Hillary Clinton handed a letter from President Barack Obama to Aung San Suu Kyi, the Nobel Prize-winning face of Myanmar's democracy movement, on Thursday, as the two women met for the first time.
Obama thanks Suu Kyi "for the inspiration you provide all of us around the world who share the values of democracy, human rights, and justice.
"We stand by you now and always," he vows in the letter, which was released by the State Department.
Clinton is having dinner with Suu Kyi at the U.S. Chief of Mission residence in Yangon, a highlight of Clinton's historic visit to Myanmar.
Earlier Thursday, Clinton met the country's new president, Thein Sein, delivering a letter from Obama to him as well.
The U.S. president told Sein he was "encouraged" that Myanmar "has undertaken several encouraging steps on the path toward reform."
But he said more needed to be done.
Clinton pushed Sein to release all political prisoners, continue democratic reforms, and cut military ties with North Korea, a senior State Department official on the trip told journalists traveling with Clinton.
"While the measures already taken may be unprecedented and certainly welcome, they are just a beginning," Clinton said of Myanmar's reforms.
She said it was "encouraging that political prisoners have been released," but said more than 1,000 others "are still not free."
"No person in any country should be detained for exercising universal freedoms of expression, assembly and conscience," she told reporters after meeting Sien.
Their meeting was "workman-like" and lasted a few hours, said the official, who spoke on condition of not being named.
Clinton held out the possibility that the United States would send an ambassador to Myanmar if reforms continue.
And she said the United States would support World Bank and International Monetary Fund trips to assess how they can help the southeast Asian nation.
On Friday, Clinton will tour Suu Kyi's home, where the activist spent most of the last two decades under house arrest.
She will also meet members of Suu Kyi's National League for Democracy, representatives of ethnic groups, and civil society organizations on Friday, the State Department said before the trip began.
Clinton's trip, the first in 50 years for an American secretary of state, was made possible by the reclusive nation's unexpected steps at democratic reform.
Ruled by a junta since 1962, Myanmar elected its new president Sein in March.
The new government freed dozens of political prisoners in October.
And on Wednesday, Suu Kyi -- who was released from her latest round of house arrest in November last year -- said she intends to run for parliament.
The developments prompted cautious optimism for the United States, which still refers to the country as Burma -- the name it used before the junta took power.
The trip, the White House said, is an indication the time could be right to forge a new relationship between the nations.
Still, Myanmar is far from a democracy -- and skepticism exists on both sides.
Journalists in the country enjoy some new freedoms, but the press is still heavily regulated. Ethnic violence still exists against Myanmar's minorities, and human rights groups estimate that more than 1,500 political prisoners are still detained.
Suspected cooperation between the government and North Korea on ballistic missiles and nuclear activity is also troubling to the United States.
As a result, the Obama administration is not ending sanctions and is not making any abrupt changes in policy.
For its part, Myanmar offered a cordial welcome to Clinton -- but the visit itself was low-key.
On Thursday, news of her trip and a photo of her greeted by officials at the Naypyidaw airport was buried in page 2 of the state-run newspaper, The Mirror.
In contrast, the front page carried a prominently placed photograph of Mikhail Myasnikovich, the prime minister of Belarus -- who arrived Thursday.