FILE PHOTO: U.S. Defense Secretary Pete Hegseth at the Oval Office of the White House in Washington, D.C., U.S., August 18, 2025. REUTERS/Kevin Lamarque/ File Photo

WASHINGTON (Reuters) -U.S. Defense Secretary Pete Hegseth on Wednesday said the Pentagon has issued a formal letter of concern after learning that Microsoft was using Chinese nationals to service Pentagon cloud environments, which he described as "a breach of trust."

"We're requiring a third-party audit of Microsoft's digital escorts program, including the code and the submissions by Chinese nationals," Hegseth said in a video posted on X.

After a report by investigative journalism publication ProPublica, Microsoft in July said it has ended the practice of using China-based engineers to provide technical support to the U.S. military under the supervision of U.S. "digital escorts".

(Reporting by Jasper Ward)