Two key materials used in the manufacture of computer chips are being restricted by the Chinese government.

The world’s largest producer of gallium and germanium, China, will require special licenses for exports starting next month.

It follows Washington’s efforts to restrict Chinese access to some advanced microprocessors.

Janet Yellen, US Treasury Secretary, is scheduled to visit Beijing just days before the announcement.

According to the Chinese Ministry of Commerce, the restrictions are necessary to protect national security and interests.

These silvery metals are used in semiconductors, communications, and military equipment. As well as solar panels, they are also used in other products.

The world’s two largest economies are at odds over semiconductors, which power mobile phones and military hardware.

As a result, the US has taken steps to restrict China’s access to technology it fears will be used for military purposes, such as chips that are used for supercomputing and artificial intelligence.

Washington announced in October that it would require licenses from companies exporting chips to China using US tools or software, regardless of where they were made.

Countries such as the Netherlands and Japan have joined the effort.

Some semiconductor manufacturing equipment will be restricted from being exported by the Netherlands starting last week.

Earlier this year, the Netherlands announced that it would restrict its exports of “most advanced” microchip technology.

As part of the global microchip supply chain, ASML, a Dutch chip equipment maker, is expected to be affected by the controls.

As a result, Japan plans to restrict some of its exports of computer chips.

23 types of semiconductor manufacturing equipment will be affected by the measures announced in March.

In response to Washington’s export controls, China has frequently called the US a “tech hegemony”.

Lockheed Martin and other US military firms have been subjected to restrictions in recent months by Beijing.

During a four-day visit to China from Thursday, US Treasury Secretary Janet Yellen warned against breaking ties between Washington and Beijing.

“In my opinion, China and the United States both benefit from trade and investment that is as open as possible, and it would be disastrous for us if we tried to decouple from China,” she told Congress last month.