Barack Obama is touring Southeast Asia to showcase foreign policy achievement and reinforce the U.S. role as a counterweight to China.
Obama leaves today for a four day trip to Thailand, Myanmar and Cambodia, his first trip abroad since June and his fourth to Asia.
Nearly a thousand demonstrators rallied in the Cambodian capital yesterday ahead of an international summit meeting, hoping to draw attention to what they say are human rights violations in the country.
The rally came ahead of the Association of South East Asian Nations (ASEAN) meeting and East Asia Summit which will bring together Barack Obama and Chinese Premier Wen Jiabao as well as the heads of states of South Korea and Japan.
"We want him (Barack Obama) to help people whose land has been taken and people who have been affected unjust actions by the country.
"We will ask Barack Obama to help all of us and we hope he will find justice for everyone of us in Cambodia," said a 39 year old rally participant Bo Chorvy.
Human rights groups have argued that Obama's trip to Myanmar is premature and that, in seeking to find allies in the region, Obama has been less attentive to repressive regimes such as that of Cambodia's longtime Prime Minister Hun Sen.
Obama aides acknowledge that Myanmar can still do better and say Obama will raise U.S. concerns about Cambodia's crackdowns on dissidents and civil society groups in the meeting with Hun Sen.