WASHINGTON 

US Sen. Tom Cotton on Thursday sent a letter to Secretary of Defense Pete Hegseth urging him to ban anyone who is not an American from accessing Department of Defense (DoD) systems.

"The language in current DoD policy guidance allows non-U.S. citizens to access DoD systems, which I believe should be addressed immediately," wrote Cotton. "Foreign persons should never be allowed to access DoD systems, regardless of whether a U.S. citizen is supervising.”

The agency, particularly the Under Secretary of Defense for Intelligence and Security, has the authority to immediately make the policy changes, he said, adding: "I urge you to do so now."

Congress must prohibit non-US citizens from accessing DoD systems under "any circumstances" and mandate the DoD to revise its policies to comply with the prohibition, said Cotton.

The letter comes amid broader efforts to scrutinize foreign influence within US defense operations, particularly in light of tensions with China.

Cotton referenced concerns about Microsoft's operations in China and requested a full briefing from the Pentagon on potential vulnerabilities in its cloud and software contracts by Sept. 5.

Last month, Hegseth responded swiftly to concerns by Cotton about reports that Microsoft has been using engineers in China to maintain DoD systems.

"Spot on Senator. Agree fully. Our team is already looking into this ASAP," Hegseth wrote on X. "Foreign engineers — from any country, including of course China — should NEVER be allowed to maintain or access DoD systems.”