President Barack Obama wrapped up his three-country tour Tuesday at the Southeast Asia summit in Cambodia.

White House officials made it clear the president's visit isn't an endorsement of Cambodia's Prime Minister Hun Sen, who is often criticized for his violent, authoritarian rule.

The nation has a well-known history of human rights abuse, including Pol Pot's infamous Khmer Rouge regime which killed nearly 2 million Cambodians in the 1970s.

During what's being called a "tense" meeting with the prime minister Monday, Obama voiced his concerns over the situation.

"[Obama] highlighted a set of issues that he was concerned about within Cambodia, in particular I would say the need for them to move towards elections that are fair and free, the need for an independent election commission associated with those elections, the need to allow for the release of political prisoners, and for opposition parties to be able to operate," Deputy National Security Adviser Ben Rhodes said.

"He highlighted, for instance, one case of a radio broadcaster who's been sentenced to many years in prison simply for something that they said on the radio," he added. "He discussed the issue of land seizures, which have been a challenge for the people of Cambodia."

CBN's George Thomas spoke with Barnabas Mam, Asia regional director for Ambassadors for Christ.

He is one of only 200 Christians to survive the Killing Fields of Cambodia. He's written a book about the experience called, Church Behind the Wire. Click play to watch.