WASHINGTON The Pentagon holds a strategic stockpile for germanium but currently has no inventory reserves for gallium, a spokesperson said on Thursday, after China announced export restrictions on the two metals used in semiconductors.

"The (Defense) Department is proactively taking steps using Defense Production Act Title III authorities to increase domestic mining and processing of critical materials for the microelectronics and space supply chain, including gallium and germanium," the spokesperson said.

Germanium is used in high-speed computer chips, plastics and military applications such as night-vision devices as well as satellite imagery sensors. Gallium is used in radar and radio communication devices, satellites and LEDs.

China's abrupt announcement on Monday of controls from Aug. 1 on exports of some gallium and germanium products, also used in electric vehicles (EVs) and fibre optic cables, has sent companies scrambling to secure supplies and bumped up prices.

The move has ramped up a trade war with the United States and could potentially cause more disruptions to global supply chains.

China President Xi Jinping, a day after the curbs were unveiled in a virtual address to leaders attending the Shanghai Cooperation Organisation summit, called on nations to spurn decoupling and avoid severing supply chains, state media reported.

(Reporting by Idrees Ali and Phil Stewart; Additional reporting by Rami Ayyub; Editing by Doina Chiacu and Mark Porter)