"We have watched as you and your government have continued the steady process of reform, and we've been pleased to respond with specific steps that recognize the government's efforts and encourage further reform," Clinton told the leader of the South Asian country formerly called Burma, the U.S. State Department reported on its website.
"And in recognition of the continued progress toward reform and in response to requests from both the government and the opposition, the United States is taking the next step in normalizing our commercial relationship. We will begin the process of easing restrictions on imports of Burmese goods into the United States. We hope this will provide more opportunities for your people to sell their goods into our market."
In response, Thein Sein said meetings with Clinton in the past have helped strengthen bilateral relations, including raising diplomatic ties to ambassadorial level, and that his people would be "very pleased" with the latest development.
Thein Sein, a former general whose civilian-led government came to power 18 months ago after decades of military rule, said, "We still need to continue our path on democratic reforms, but with the recognition and the support from the champion of democracy like the United States, it has been an encouragement for us to continue our chosen path."
Clinton did not rule out more U.S. concessions, while "at the same time working with you and supporting those who are hoping that the reform will be permanent and progress will be continuing."
Separately, the U.S. Treasury Department said it looked forward to collaborating with the Myanmar government "on mutual issues of concern to combat international money laundering and the financing of terrorism."
In previous actions, the United States lifted a ban on U.S. investments in Myanmar, and last week Thein Sein was taken off a list of those facing sanctions, The New York Times reported.
During her recent visit to Washington, Myanmar opposition leader and Nobel Peace Prize Laureate Aung San Suu Kyi, who is now a member of Parliament after being under house arrest for years, had called for steps to normalize U.S.-Myanmar commercial ties.
Political experts told the Times the decision to ease import restrictions would help impoverished Myanmar, which is also rich in minerals.
"The timing of this announcement is a big win for Thein Sein," Suzanne DiMaggio, the Asia Society's vice president for global policy programs, told the Times. "He will return from his first visit to the U.S. as Myanmar's president with a major boost to his reform agenda. It's a 'concrete deliverable' that will go a long way toward muffling critics and hard-liners at home."
"What this is intended to do is help a Burmese economy that is more than resource-based in terms of exports," an Obama administration senior official told the Times, adding he hoped such actions would create jobs and promote industries beyond natural gas, oil and timber in that country.
Another official told the Times the administration is satisfied with Myanmar leaders' efforts to reconsider military ties with North Korea.