The phone has been full of surprises, with many in the West wondering how Huawei "would have the ability to manufacture such an advanced smartphone following sweeping efforts by the United States to restrict China's access to foreign chip technology."

When researchers from TechInsights got the back off one of the Pros, they discovered two SK Hynix memory chips which should not have been there.

Shares in Hynix fell more than four per cent 12 gigabyte LPDDR5 chip and 512 GB NAND flash memory chip were found inside the Huawei handset.

There are restrictions on what SK Hynix can ship to China, and it is still being determined how the chips came to be there.

A Hynix spokesperson told CNN Friday that it was aware of its chips being used in the Huawei phone and had started investigating the issue.

It insisted that it has not done any business with Huawei since introducing the US restrictions against the company.

Huawei must have purchased the memory chips from the secondary market and not directly from the manufacturer. Huawei may have accumulated a stockpile of components before the US export curbs kicked in fully.