PHNOM PENH -- U.S. senior diplomat Wendy Sherman says Washington has "serious concerns" about China's "military presence" at a naval base undergoing Beijing-backed expansion on Cambodia's coast.
Sherman, the deputy secretary of state, made the remarks during a two-hour meeting with Cambodia's Prime Minister Hun Sen on Tuesday in Phnom Penh, which she described on Twitter as "candid."
The senior Joe Biden administration official also called on Cambodia to drop "politically motivated charges against members of the political opposition, journalists and activists," according to a statement released by the U.S. Embassy in the country.
Sherman is on an 11-day diplomatic tour that includes three stops in Southeast Asia, a theater of intensifying U.S.-China tension. The delegation's decision to include Cambodia, alongside Indonesia and Thailand, comes at a time when Phnom Penh is seen to be moving increasingly close to Beijing, its top source of aid and investment.
Hun Sen defended his close ties with China last month while speaking at Nikkei's Future of Asia conference.
A potential flashpoint in the region has been Ream Naval Base in Cambodia's Sihanoukville Province -- facing the Gulf of Thailand -- where China is backing an expansion of facilities. In 2019, a senior Pentagon official expressed concerns that plans may exist to host Chinese assets at the site -- a suggestion Cambodian and Chinese leaders have rejected.
In a March hearing at the U.S. Senate Armed Services Committee, then commander of the U.S. Indo-Pacific Command Adm. Philip Davidson told lawmakers that in September 2020, Cambodia razed a U.S- built facility on Ream Naval Base that served as the headquarters for the National Committee on Maritime Security.
Citing a report that said the move was to make way for a Chinese naval base, Davidson said, "The United States and other countries in the region are concerned about the expansion of PRC influence in Cambodia and its implication for regional security," using the acronym for China's formal name.
Last week, the Center for Strategic and International Studies, a U.S. think tank, released new satellite images showing that two new buildings have been recently constructed at the site.
A top Royal Cambodian Navy official told Nikkei Asia last October that the Chinese government was supporting a project to expand the port, which will include a newly dredged port and a ship repair facility.
On Tuesday, Sherman "sought clarification on the demolition of two U.S.-funded buildings at Ream without notification or explanation and observed that a PRC military base in Cambodia would undermine its sovereignty, threaten regional security, and negatively impact U.S.-Cambodia relations," according to the American statement.
It added: "The deputy urged Cambodia's leadership to maintain an independent and balanced foreign policy, in the best interests of the Cambodian people."
Speaking to the Phnom Penh Post this week, Cambodian Minister for Defense Tea Banh defended the use of Chinese funds to upgrade Ream and reiterated denials that it would be used as a base for China.
"Why can't Cambodia seek assistance to develop the country?" he said.
But on Monday, while Sherman was in the region, China flew 16 aircraft belonging to the People's Liberation Army Air Force close to Malaysian airspace, triggering the latter to scramble jet fighters.
The Malaysian Foreign Ministry released a statement Tuesday saying it will issue a note of diplomatic protest and summon the Chinese ambassador to explain the "breach of the Malaysian airspace and sovereignty."
Cambodia's drift into Beijing's orbit has coincided with the deterioration of relations with the U.S. and European Union, which have censured Cambodia for human rights violations.
After almost losing an election in 2013, Hun Sen's government, in power for more than 30 years, has pursued a wide-ranging campaign against opponents. In 2017, it forcibly dissolved the main opposition party, the Cambodian National Rescue Party, and has since prosecuted more than 100 grassroots supporters and activists.
It has also leveled treason charges against CNRP leader Kem Sokha, linking him to a far-fetched U.S.-backed plot to overthrow Hun Sen.
During her visit, Sherman met with Sokha as well as civil society groups.
They discussed "issues of shared importance with the United States" such as "ensuring a peaceful, prosperous, sovereign and democratic future for Cambodia," the embassy wrote.
"Deputy Secretary Sherman pressed the government to reopen civic and political space in advance of the 2022 commune and 2023 national elections."
Brussels last year suspended some of Cambodia's EU trade preferences in response to the political crackdown. Lawmakers in the U.S. have also pushed for Cambodia's trade privileges to be reviewed.
Perhaps tellingly, the U.S. statement made explicit reference to what it called "generous U.S. trade benefits that have fueled economic growth in the kingdom."
In a story on Tuesday evening, Cambodia's state media outlet Agence Kampuchea Presse emphasized different topics which it said were covered in the meeting.
It said Sherman had expressed her "satisfaction" with Cambodia for its help finding remains of soldiers from the Vietnam war, its cooperation in anti-terrorism and its welcoming of a cruise ship in 2020 that was turned away from other ports because of COVID-19 concerns.
The delegations also discussed renegotiating Cambodia's U.S. debt accrued during the war, as well as investment, according to AKP.