The US Commerce Department said it believes that Chinese chipmaker Semiconductor Manufacturing International Corp (SMIC) potentially violated US export rules by producing a chip for Huawei’s Mate 60 Pro phone.

However, during a congressional hearing on Thursday, March 21, Alan Estevez, who oversees export policy at the department, said that an investigation into the possible breach was still ongoing.

The US government opened its investigation in September 2023 after it was first discovered the Huawei Mate Pro 60 contained Kirin 9000S chips. These 7nm, 5G-enabled chips are produced in China by the partly state-owned SMIC.

When asked if SMIC might have had the ability to produce the chip for Huawei using American tools, Estevez responded that while he couldn't speak to any specific findings from the investigation, the department "certainly [shares] those concerns."

The US has sought to restrict the availability of 7nm chips in China by imposing export restrictions, and SMIC was barred by the US from obtaining the machines necessary for the production of 7nm chips in late 2020. When the Department of Commerce started its investigation, at that time, the most advanced chip SMIC had been known to manufacture was a larger-scale 14nm semiconductor.

TechInsights, a semiconductor research and analysis organization that published an analysis of the component parts of the Mate Pro 60, said it also found that South Korean SK Hynix’s LPDDR5 memory had been used in the phone. However, in a statement released by the company at the time, it insisted it had not sold any of its products to the company since US sanctions were first imposed in 2020.

The US is currently engaged in a trade war with China and has imposed controls on the export of some types of chips to the country to stop it from developing advanced AI systems and to prevent it from having access to technology that could be used for military modernization and human rights abuses.

Huawei was banned from providing equipment to the US government under the Defense Authorization Act of 2018. A general import ban followed shortly thereafter, with former President Donald Trump signing a law in 2020 to prevent US rural telecom carriers from using Huawei network equipment.