PHNOM PENH, Cambodia—The United States on Wednesday accused the Cambodian government of lacking transparency about Chinese construction activities at its biggest naval base, and urged it to disclose to its people the full scope of Beijing’s military involvement. The Center for Strategic and International Studies (CSIS) on Wednesday made public what it said were satellite images showing construction in August and September of three new buildings and the start of a new road. U.S. embassy spokesperson Chad Roedemeier in a statement said that any foreign military presence at Ream would violate Cambodia’s constitution and undermine regional security. “The government of Cambodia has not been fully transparent about the intent, nature, and scope of this project or the role of the PRC military, which raises concerns about intended use of the naval facility,” he said, referring to communist China. “The Cambodian people deserve to know more about the project at Ream …