The US Commerce Department continued an investigation of Semiconductor Manufacturing International Corporation (SMIC) for allegedly producing a high-end processor for Huawei, as the government assesses possible trade sanction violations.

Under secretary of commerce for industry and security Alan Estevez suggested SMIC “potentially” violated US controls in manufacturing chips for the Shenzhen-based company, which is subject to trade restrictions, Bloomberg reported.

The launch of the Mate 60 Pro last August raised concerns in the US about the origins of the device’s 7nm processor as well as if the maker of the chip bypassed US controls. It also kicked off a debate over whether the handset supported 5G.

To produce the chipset, SMIC reportedly used chipmaking gear from ASML, Lam Research and Applied Materials imported into China before the US and the Netherlands imposed restrictions on the export of high-end machinery into the mainland in 2023.

Chinese companies don’t have access to extreme ultraviolet lithography (EUV) chip machinery, the most advance equipment, relying on the previous generation of equipment.

Radio Free Mobile founder Richard Windsor wrote back in October that without EUV it is extremely difficult to make 7nm chips with the kind of yields and volumes that would make production a commercial success.

The US government also is considering imposing new restrictions against six Chinese chipmakers believed to be supporting Huawei.