[Source: Reuters]

China on Tuesday banned exports to the United States of the critical minerals gallium, germanium and antimony that have widespread military applications, escalating trade tensions the day after Washington’s latest crackdown on China’s chip sector.

The curbs strengthen enforcement of existing limits on critical minerals exports that Beijing began rolling out last year, but apply only to the U.S. market, in the latest escalation of trade tensions between the world’s two largest economies ahead of President-elect Donald Trump taking office next month.

A Chinese Commerce Ministry directive on dual-use items with both military and civilian applications cited national security concerns. The order, which takes immediate effect, also requires stricter review of end-usage for graphite items shipped to the U.S.

Gallium and germanium are used in semiconductors, while germanium is also used in infrared technology, fibre optic cables and solar cells. Antimony is used in bullets and other weaponry, while graphite is the largest component by volume of electric vehicle batteries.

The move has sparked fresh concern that Beijing could next target other critical minerals, including those with even broader usage such as nickel or cobalt.

The United States was assessing the new restrictions, but will take “necessary steps” in response, a White House spokesperson said, without giving details.

Representatives for Trump did not immediately respond to a request for comment.

Chinese customs data show there have been no shipments of wrought and unwrought germanium or gallium to the U.S. this year through October, although it was the fourth and fifth-largest market for the minerals, respectively, a year earlier.

Similarly, China’s overall October shipments of antimony products plunged by 97% from September after Beijing’s move to limit its exports took effect.

China accounted last year for 48% of globally mined antimony, which is used in ammunition, infrared missiles, nuclear weapons and night-vision goggles, as well as in batteries and photovoltaic equipment.

This year, China has accounted for 59.2% of refined germanium output and 98.8% of refined gallium production, according to consultancy Project Blue.

Prices of antimony trioxide in Rotterdam had soared by 228% since the beginning of the year to $39,000 a metric ton on Nov. 28, data from information provider Argus showed.

Perpetua Resources (PPTA.O), opens new tab, which is developing an Idaho antimony mine with U.S. government financial support, said China is “weaponizing accessing” to minerals critical for the U.S. military and technology firms.