China did not export any germanium and gallium products in August, after export curbs kicked into effect at the start of that month for these two chipmaking metals.
Customs data on Wednesday showed that China exported zero germanium product last month, down from 8.63 metric tons in July, Reuters reported.
July germanium exports were more than double that of June's, as purchases spiked ahead of the effective date for the curbs that are part of China's escalating war with the U.S. and its allies over access to strategic technology.
There were also no exports of gallium products in August, compared to the 5.15 tons exported in July, customs data showed.
Germanium and gallium are not found naturally, and are by-products of the refineries of other metals.
Germanium is used in solar products and fiber optics, and can be employed in military applications such as night-vision goggles. Gallium is used for manufacturing the gallium arsenide chemical compound, which is used to make radio frequency chips for mobile phones and satellite communication, and semiconductors.
Citing national security concerns, China's commerce ministry imposed new restrictions requiring exporters to seek a license to ship some gallium and germanium compounds starting Aug. 1.
Applications for these export licenses must identify importers and end users and stipulate how these metals will be used.
In October, the U.S. had launched sweeping rules aimed at cutting off exports of key chips and semiconductor tools to China. The measures are believed to have the potential to cripple China's ambitions to boost its domestic technology industries.
The U.S. has also lobbied key chipmaking nations and allies, like the Netherlands and Japan, to introduce export restrictions of their own.