China has intensified enforcement of its import restrictions on US chips, including those from Nvidia (NVDA.O), the Financial Times reported, as Beijing sharpens its focus on promoting domestically produced semiconductors.

Chinese customs officials were dispatched to key ports to conduct strict checks on semiconductor shipments, the newspaper said on Friday, citing unidentified sources.

China customs officials did not immediately respond to Reuters’ request for comment, while an Nvidia spokesperson declined to comment on the report.

The newspaper stated that the inspections initially targeted Nvidia’s H20 and RTX Pro 6000D, which are designed to adhere to US export controls.

The checks have been extended to include all advanced semiconductor products that breach US export curbs, the report said.

Reuters could not immediately verify the report.

The extent to which China has access to Nvidia’s world-leading chips has been a key point of friction between the US and China.

The Financial Times (FT) newspaper had previously reported that at least one billion USD worth of Nvidia’s top AI chips were smuggled and sold in China in the three months from May. Reuters could not independently verify the report.

Nvidia has a new AI chip, RTX6000D, tailored for the Chinese market, Reuters reported last month, but it has seen only lukewarm demand with some major tech firms opting not to place orders.

In August, US President Donald Trump flagged the possibility of allowing Nvidia to sell more advanced chips in China.

Authorities in China have previously accused Nvidia of violating anti-monopoly law. They have also ordered top tech firms to halt purchases of Nvidia’s AI chips and cancel existing orders, FT reported in September.

Despite advances by Huawei and other Chinese chip firms in recent years, people involved in engineering operations at Chinese tech firms say Nvidia’s chips perform better.