(Bloomberg) -- The US has called for more information about a naval base in Cambodia after a rare visit by Chinese warships, renewing concern Beijing wants a military facility in the Southeast Asian nation.

“The Cambodian people, neighboring countries, Asean and the region more broadly would benefit from transparency on activities at Ream,” Wesley Holzer, an spokesman at the US Embassy in Phnom Penh, said Thursday when asked about the Chinese vessels.

“The United States and countries in the region have consistently expressed concern about the intent, nature and scope of construction at Ream Naval Base,” Holzer said in a written response to a question from Bloomberg News. This included the role China’s military “is playing in this process and in future use of the facility.”

Several Chinese vessels recently became the first known foreign warships to dock at Ream, Radio Free Asia reported Tuesday. Cambodian Defense Minister Tea Seiha said on social media on Sunday that he visited the ships “in preparation for training.”

When asked about the warships’ visit at a regular press briefing in Beijing on Thursday, Foreign Ministry spokesman Wang Wenbin said “China and Cambodia enjoy deep friendship.” “The two sides have productive cooperation,” he added.

Cambodia’s Defense Ministry didn’t respond to a request for comment. 

China has supported Cambodia’s redevelopment of the base on the Gulf of Thailand, an effort that observers say is strategically vital for Cambodia’s maritime governance. The US has said a military facility at Ream would be China’s first overseas base in the Indo-Pacific. In late 2022, President Joe Biden expressed concern about possible activities by China’s military there. 

A Pentagon report earlier this year said that China has sought to “normalize its presence overseas and build closer ties to foreign militaries.” In 2022, Beijing had an overseas peacekeeping force of more than 2,000 personnel and continued work on a People’s Liberation Army facility at the Cambodian base, it said.

Read: Cambodia Denies Report China Building Secret Naval Facility

Cambodia has dismissed allegations that China is secretly building a naval facility on its soil. Beijing has said renovations at Ream were “aimed at strengthening the Cambodian navy’s ability to safeguard maritime territorial integrity and combat maritime crimes.”

In 2021, the US leveled sanctions against two senior Cambodian defense officials for corruption related to the naval base.

The US has been bolstering its security relationships in the region to counter China’s growing military prowess.

(Updates with comment from China’s Foreign Ministry.)

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