Apple and Amazon are denying a report claiming spy chips from China were found in hardware they use.

According to a report by Bloomberg, tiny microchips were found on motherboards of servers assembled by the San Jose company Super Micro Computer.

An official cited anonymously by Bloomberg said the supply chain-level breach affected almost 30 companies, including Amazon Web Services and Apple.

Three years ago, Amazon considered a possible acquisition of Elemental Technologies – which used servers built by Super Micro – to help bolster its Web Services, according to the report, but grew wary after uncovering security issues, including the microchips. Amazon eventually acquired Elemental in September 2015.

In 2015, three senior insiders at Apple – once a big customer of Super Micro – discovered the malicious chips, the report said. Apple stopped working with Super Micro a year later for undisclosed reasons.

In a statement published Thursday, Apple denied the Bloomberg report, claiming malicious chips were never uncovered.

"We are deeply disappointed that in their dealings with us, Bloomberg’s reporters have not been open to the possibility that they or their sources might be wrong or misinformed," read Apple's statement.

Amazon called the report "erroneous" in a blog post published Thursday. "At no time, past or present, have we ever found any issues relating to modified hardware or malicious chips in Super Micro motherboards in any Elemental or Amazon systems," the company said.

In a statement released Thursday, Bloomberg News said the story required more than a year of reporting and more than 100 interviews. They also said 17 individual sources confirmed the manipulated hardware.

"We stand by our story and are confident in our reporting and sources," said Bloomberg News.

U.S. investigators found the malicious chips were added to the motherboards during the manufacturing process in China, the Bloomberg report said. An unnamed government official told Bloomberg the goal was securing long-term access to government networks and "high-value corporate secrets."

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