Secretary of State John F. Kerry departs a tour of the National Museum of Cambodia in Phnom Penh on Tuesday. (Jacquelyn Martin/AP)

Secretary of State John F. Kerry met Tuesday with Cambodian leaders to express concern about the government’s record on human rights and corruption in a visit that otherwise focused on forging trade and investment ties.

Kerry held talks with Prime Minister Hun Sen, who has been in power for three decades, and Foreign Minister Hor Namhong, but he also made a point of meeting with Kem Sokha, the acting head of the opposition in Cambodia. The opposition has had an acting head since November, when the official leader, Sam Rainsy, went into exile after he was ordered arrested for allegedly defaming the foreign minister.

In his one-day visit to Cambodia, Kerry acknowledged both the legacy of past wars and the advances the country has made since.

But he said respect for human rights and good governance is critical to an improvement in relations between Washington and Phnom Penh.

“In my discussions today, I emphasized the essential role that a vibrant, democratic system plays in the development of a country and the legitimacy of its political system,” Kerry told reporters before departing for Beijing. “Democratic governments have a responsibility to ensure that all elected representatives are free to perform their responsibilities without fear of attack or arrest.”

Although this was his first trip to Phnom Penh as secretary of state, he recalled that he came to Cambodia several times as a member of the Senate Foreign Relations Committee to help establish an international tribunal to try former Khmer Rouge figures.

Under the leadership of Pol Pot, the Khmer Rouge ruled Cambodia from 1975 to 1979, a time when an estimated 1.7 million Cambodians died from violence, hunger or other mistreatment. Kerry also traveled here when he co-chaired a Senate committee trying to account for Americans lost during the Vietnam War era, in Cambodia as well as Vietnam and Laos.

“So I am very, very conscious in returning here now in 2016 at the extraordinary distance traveled by Cambodia,” Kerry said.

In his official talks here, as in Laos, Kerry was laying the groundwork for a summit President Obama will host next month for the 10-member Association of Southeast Asia Nations (ASEAN) at the Sunnylands estate in California.

The administration has been trying to “rebalance” its foreign policy to pay more attention to Asia, which is expected to fuel much of the world’s economic growth in the future. Cambodia has one of the fastest-growing economies in Asia, and the United States is its largest export market.

“I’d just emphasize that the United States is an Asia-Pacific nation,” Kerry said, adding, “And we are deeply committed to our partnership with Cambodia and with all the members of ASEAN on a regional and global basis.”

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