WASHINGTON — The Obama administration says it is easing restrictions on U.S. investment and trade in Myanmar to encourage business development in the impoverished country and in recognition of its political reforms.

The administration also named on Thursday the current special envoy to Myanmar, Derek Mitchell, as its first ambassador to the country in 22 years. The U.S. is currently represented by a lower-level diplomatic officer.

Myanmar's reforms over the past year or so have seen it emerge from decades of direct military rule and diplomatic isolation. In a sign of its international rehabilitation, the Asian nation's Foreign Minister Wunna Maung Lwin was meeting with Secretary of State Hillary Rodham Clinton at the State Department.

Despite the easing of restrictions, U.S. companies would still be barred from doing business with firms associated with the country's powerful military, a senior administration official told The Associated Press. The official spoke on condition of anonymity to disclose the information before a formal announcement later Thursday.

The White House is also keeping its framework of hard-hitting sanctions in place for now, saying Myanmar's democratic reforms are still "nascent."

"We continue to have concerns, including remaining political prisoners, ongoing conflict and serious human rights abuses in ethnic areas," said a notification to Congress issued Thursday, signed by President Barack Obama.

The administration had announced after democracy leader Aung San Suu Kyi's election to parliament in April that it planned to ease a ban on American investment in the country also known as Burma. That has fueled intense debate in Washington on how and at what pace the U.S. should ease policies that have long punished Myanmar for rights abuses and suppression of democracy.

U.S. businesses and some lawmakers are pushing for economic sanctions to be lifted and point to the European Union's recent suspension of its restrictions, which could now leave American corporations at a competitive disadvantage — not least in the potentially lucrative oil, gas and mining sectors.

Human rights groups are concerned that the Obama administration is moving too fast to reward the reforms of President Thein Sein, despite the continuing detention of hundreds of political prisoners and ethnic violence.

The senior administration official said that although Clinton telegraphed the likely easing of some controls, Thursday's announcement goes slightly farther than earlier planned, in recognition of political improvements in Myanmar including the seating of Suu Kyi in parliament, along with dozens of her party members.

The official said the U.S. would allow a broad range of economic activity, adding that responsible business development was important for keeping Myanmar on a reform path.

There have been voices of support on both sides of Congress for easing economic restrictions. Democrat Sen. Jim Webb, a longtime advocate of engagement with Myanmar who is among several senators who will meet with Wunna Maung Lwin, said the visit was an "appropriate time" to lift economic sanctions.

Republican Sen. John McCain has been a little less forthright and won a cautious endorsement Tuesday from Suu Kyi, whose opinion is key to shaping U.S. policy.

McCain said sanctions should be suspended while the U.S. maintains restrictions against individuals and entities that violate human rights and "plunder the nation's resources." He said American companies should not do business with state-owned firms dominated by the military and should adhere to established standards of corporate responsibility.

The devil of such restrictions would be in the details. If U.S. companies were barred from working with state-owned enterprises like the country's oil and gas company — which is currently not included on a U.S. list of blacklisted Myanmar entities — that would effectively exclude them from the petroleum sector, where the previous military regime earned billions.

Human Rights Watch is demanding the imposition of binding rules on corporate responsibility for U.S. companies working in Myanmar and revision of the blacklist that has not been updated for at least three years.

"Tough rules are needed to ensure that new investments benefit the people of Burma and don't fuel human rights abuses and corruption, or end up strengthening the military's control over civilian authorities," John Sifton, the group's Asia advocacy director, said in a statement.