Washington in July cleared Nvidia to resume sales of the H20 chips to China, reversing an effective April export ban. Beijing has since sought supporting documentation on potential risks, including vulnerabilities,

Nvidia earlier this month said the U.S. government is giving permission to sell its H20 microchip again in China — but now a Chinese regulator is raising a red flag.

Chinese authorities summoned Nvidia Corp. to discuss alleged security risks related to its H20 chips, casting doubt over the domestic business of the world’s most valuable company weeks after co-founder Jensen Huang met senior officials in Beijing.