SAN FRANCISCO, July 18 (Reuters) -

Microsoft ( MSFT ) on Friday said it will stop using

China-based engineers to provide technical assistance to the

U.S. military after a report in investigative journalism outlet

ProPublica sparked questions from a U.S. senator and prompted

Defense Secretary Pete Hegseth to examine the matter.

The report detailed Microsoft's ( MSFT ) use of Chinese engineers to

work on U.S. military computing systems under the supervision of

U.S. "digital escorts" hired through subcontractors who have

security clearances but often lacked the technical skills to

assess whether the work of the Chinese engineers posed a

cybersecurity threat.

Microsoft ( MSFT ), a major contractor to the U.S. government, has

had its systems breached by Chinese and Russian hackers. It told

ProPublica that it disclosed its practices to the U.S.

government during an authorization process.

On Friday, Microsoft ( MSFT ) spokesman Frank Shaw said on social

media website X that the company changed how it supports U.S.

government customers "in response to concerns raised earlier

this week .... to assure that no China-based engineering teams

are providing technical assistance" for services used by the

Pentagon.

Earlier on Friday, Senator Tom Cotton, an Arkansas

Republican who chairs the chamber's intelligence committee and

also serves on its armed services committee, sent the letter to

Defense Secretary Pete Hegseth about Microsoft's ( MSFT ) reported

practices. Cotton asked the U.S. military for a list of

contractors that use Chinese personnel and more information on

how U.S. "digital escorts" are trained to detect suspicious

activity.

"The U.S. government recognizes that China's cyber

capabilities pose one of the most aggressive and dangerous

threats to the United States, as evidenced by infiltration of

our critical infrastructure, telecommunications networks, and

supply chains," Cotton wrote in the letter. The U.S. military

"must guard against all potential threats within its supply

chain, including those from subcontractors."

In a post on social media site X on Friday, Hegseth said

Cotton's concerns were "spot on" and that the Defense Department

is looking into Microsoft's ( MSFT ) practices.

"Foreign engineers - from any country, including of course

China - should NEVER be allowed to maintain or access (Defense

Department) systems," Hegseth said in the post.