Obama to Host Burmese President
President Thein Sein is to meet Barack Obama in Washington, in the first state visit by a Burmese leader since 1966.
The US said the visit showed commitment to helping "governments that make the important decision to embrace reform".
The US has hailed recent changes in the formerly military-ruled state, including the release of dissidents and relaxed censorship.
However, activists have raised concerns over the sustainability of the reforms and religious violence in Burma.
Thein Sein's invitation to the White House demonstrates Mr Obama's determination to keep building relations with the current government, despite warnings from human rights groups that he is making concessions too quickly, the BBC's South East Asia correspondent Jonathan Head reports.
The US administration believes it needs to encourage the Burmese president to continue his reforms; it has suspended most but not all sanctions, our correspondent adds.
Burma has launched a series of reforms since establishing a nominally civilian government in 2011, ending almost 50 years of military rule.
Thein Sein heads an administration that was elected in November 2010 in the country's first elections in two decades. The Aung San Suu Kyi-led opposition has a small presence in parliament after a landslide win in by-elections in April 2012 largely deemed free and fair.
Speaking at a forum at the office of US broadcaster Voice of America on Sunday, Thein Sein said US-Burma relations had "greatly improved thanks to the policies of President Obama".
"For our political reforms, we also need more economic development," he said.
He defended the allocation of 25% of seats in Burma's parliament to the military - something entrenched in the country's 2008 constitution.
"[The military] is a defensive force. You cannot deny their place in politics," he said.
International groups have also voiced concerns about serious religious violence in Burma in recent months.
At least 40 people were killed in anti-Muslim riots in central Burma last month, while widespread unrest in 2012 between Buddhists and Muslims in Rakhine state left nearly 200 people dead, and thousands of Rohingya Muslims displaced.
Democratic Congressman Joe Crowley said in a statement that he was "incredibly concerned about the facts on the ground in Burma, including human rights violations against ethnic nationalities".
Jennifer Quigley, from the US Campaign for Burma, said: "President Obama is sending the message that crimes against humanity by state forces against ethnic and religious minorities in Burma will be ignored by his administration."
Hundreds of political prisoners have been freed - more than 20 were pardoned prior to Thein Sein's trip. However, activists say that more remain behind bars, and have described the timing of the releases as "manipulative".
On Friday, Thein Sein's office director Zaw Htay denied that the government was using political prisoners as "tools".