Barack Obama becomes the first US president to visit Burma, in a six-hour trip that acknowledged the country's steps towards democratic change.

Barack Obama embraces Aung San Suu Kyi (Reuters)

President Obama met with opposition leader Aung San Suu Kyi in the trip, and was due to meet Prime Minister Thein Sein, who has been behind many of the country's recent reforms.

However, some human rights groups have said that Burma's poor human rights record, including the continued detention of hundreds of political prisoners, means the country has not yet won the right to a personal visit from the US president.

"Obama's trip to Burma risks providing an undeserved seal of approval to the military-dominated government that is still violating human rights," Brad Adams, Asia director at Human Rights Watch, said before the president arrived in the region.

President Obama said he would be pushing the government for further improvements on its human rights record. "I don't think anybody is under the illusion that Burma's arrived, that they're where they need to be," he told a news conference as he began a three-country Asian tour.

"On the other hand, if we waited to engage until they had achieved a perfect democracy, my suspicion is we'd be waiting an awful long time."

Coinciding with the trip, the Burmese government released 66 detainees, 44 of whom are believed to be political prisoners.

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Democratic advances

The US has lifted a number of economic penalties against Burma in the light of democratic steps it has taken, including relaxing censorship, freeing political prisoners, and culminating in a successful by-election win for Ms Suu Kyi's National League for Democracy party in April this year.

The president was also expected to announce today a resumption of aid programmes in Myanmar, expected to total around $170m, dependent on further reforms.

However, violence between majority Buddhists and the Rohingya Muslim minority in western Myanmar escalated in October. President Obama's aides said attacks on the minority community were a top concern for the trip. At least 167 people were killed in two periods of violence in the Rakhine state in June and October.

Read more about the violence against the Rohingya here.

The president's visit to Burma was a part of a three-country tour, which also includes Thailand and Cambodia.