Taiwan Semiconductor Manufacturing Company suspended shipments to China-based chip designer Sophgo after a chip it made was found on a Huawei AI processor, according to two people familiar with the matter.

Sophgo had ordered chips from TSMC that matched the one found on Huawei’s Ascend 910B, the people said. Huawei is restricted from buying the technology to protect U.S. national security. Reuters could not determine how the chip ended up on the Huawei product.

Tech research firm TechInsights discovered the TSMC chip on Huawei’s Ascend 910B when it took apart the multi-chip processor, a different source told Reuters on Tuesday. Alerted to the finding, about two weeks ago TSMC notified the U.S., the source said.