China’s Cyberspace Administration said on Thursday it had summoned representatives of Nvidia Corp. to explain “serious security risks” allegedly found in the U.S. company’s H20 artificial-intelligence chip, a processor tailored for the Chinese market. The regulator cited reports that the hardware could be remotely tracked, geolocated or shut down through hidden back-door functions, and ordered the company to provide a detailed explanation and supporting technical documents. The investigation comes less than three weeks after Washington lifted an export ban on the H20, clearing Nvidia to resume shipments that had been paused since April. Lawmakers in the United States have meanwhile proposed legislation that would compel chipmakers to embed location-tracking features in advanced processors exported abroad—concerns the CAC said prompted its own review. Nvidia, which still derives a mid-single-digit share of revenue from China, said in a statement that it builds no back doors into its products and that cybersecurity is “critically important.” The company has reportedly placed orders with Taiwan Semiconductor Manufacturing Co. for about 300,000 H20 units to meet pent-up Chinese demand, a sales push that could be jeopardised if Beijing’s probe results in new restrictions or delays.