A Chinese government spokesman has sidestepped questions about a report that its spies inserted chips into computer equipment that might allow them to hack into U.S. companies and government agencies.

Do you feel that you still need China to respond to these statements? - Lu Kang, Chinese government spokesman

The spokesman, Lu Kang, responded to questions Monday from reporters by directing them to statements by the equipment supplier and customers including Apple and Amazon. Those companies denied any knowledge the equipment had been altered.

Lu said, "Do you feel that you still need China to respond to these statements?"

Bloomberg News cited unidentified U.S. officials as saying malicious chips were inserted into equipment supplied by Super Micro Computer Inc. to American companies and government agencies.

Bloomberg said the components included code that caused the products to accept changes to their software and to connect to outside computers.

On Sunday, Apple Inc's top security officer told Congress on Sunday that it had found no sign of suspicious transmissions or other evidence that it had been penetrated in a sophisticated attack on its supply chain. (REUTERS)

On Sunday, Apple Inc's top security officer told Congress on Sunday that it had found no sign of suspicious transmissions or other evidence that it had been penetrated in a sophisticated attack on its supply chain.

Apple Vice President for Information Security George Stathakopoulos wrote in a letter to the Senate and House commerce committees that the company had repeatedly investigated and found no evidence for the main points in a Bloomberg Businessweek article published on Thursday, including that chips inside servers sold to Apple by Super Micro Computer Inc allowed for backdoor transmissions to China.

The letter follows statements on Friday by Britain's National Cyber Security Centre and on Saturday by the U.S. Department of Homeland Security that those agencies have no reason to doubt denials from Apple and Amazon.com Inc that they had discovered backdoored chips.

Bloomberg said on Friday it stood by its story, which was based on 17 anonymous sources.