The Department of Homeland Security said this weekend it had "no reason to doubt" denials from Apple and Amazon of a report that Chinese spies placed surveillance chips in their server hardware.
The report by Bloomberg News, which cited unidentified U.S. officials, said the malicious chips were inserted into equipment supplied by Supermicro Computer Inc. to American companies and government agencies. It also said Chinese military operatives added components to Supermicro products made at factories in China, including code that caused the products to accept changes to their software and to connect to outside computers.
Apple denied the report on Thursday, telling Fox News that the story was "inaccurate" and its sources "wrong or misinformed." In a statement of its own, Amazon said it had found "no evidence to support claims of malicious chips or hardware modifications."
In a statement released Saturday, the DHS said that it was "aware" of the report, but added: "Like our partners in the UK, the National Cyber Security Centre, at this time we have no reason to doubt the statements from the companies named in the story."
Supermicro, headquartered in San Jose, California, denied its products contained malicious chips.
"Supermicro has never found any malicious chips, nor been informed by any customer that such chips have been found," said a company statement.
The Chinese Foreign Ministry issued a statement calling the claims in the story "gratuitous" and proclaimed: "China is a resolute defender of cybersecurity."
Apple ended its relationship with Supermicro in 2016, for what it called unrelated reasons. In a statement to CNBC, Apple said it found a single infected driver on one Supermicro server in a lab, calling it a one-time event.
Fox News' Chris Ciaccia and The Associated Press contributed to this report.