The commerce department said Huawei’s Ascend processors are nailed under export controls because they almost certainly involve US technology.

Its Bureau of Industry and Security, which polices exports, announced on Tuesday that it had “issued guidance that using Huawei Ascend chips anywhere in the world violates US export controls”.

Sources familiar with the matter stressed that no new rule was cooked up, but companies needed reminding that slapping Huawei chips into anything was a breach needing rare-as-hen’s-teeth licences.

Akin Gump, export control lawyer, Kevin Wolf said: “The guidance is not a new control, but rather a public confirmation of an interpretation that even the mere use anywhere by anyone of a Huawei-designed advanced computing [integrated circuit] would violate export control rules.”

The bureau namechecked three particular Huawei Ascend chips, 910B, 910C, and 910D, which are presumed contaminated with US-origin technology or produced with kit made from US software.

Huawei is already shipping AI chip “clusters” inside China that it claims outgun leading US chipmaker Nvidia’s comparable kit on critical measures like compute and memory. While one 910C chip cannot quite match Nvidia’s top kit, loads of them bundled together allegedly crush Nvidia’s cluster systems.

The Shenzhen tech behemoth flogs the Ascend 910B and 910C processors to Chinese firms and is ramping up production, hoping to fill the gaping hole left by Chinese customers being shut out of Nvidia’s gear.

The cocaine nose jobs of Wall Street are starting to fret that Huawei will soon flog AI processors at home and abroad, eating Nvidia’s lunch.

Nvidia chief Jensen Huang said last month that Huawei was “one of the most formidable technology companies in the world” and warned that US policies must help his firm stay competitive globally.