Japan warned Tuesday it will oppose any violations of World Trade Organization rules and other international agreements as China tightens export controls on two metals needed to make chips for the telecom and electric-vehicle sectors.

Japanese Trade Minister Yasutoshi Nishimura said Tokyo will watch how China implements planned export restrictions on germanium and gallium and seek answers on the intent behind the move.

“If any measures are unfair toward Japan in light of international rules such as those under the WTO, we will act accordingly,” Nishimura told reporters at a regular news conference. Tokyo does not consider China’s curbs as a reaction to Japan shoring up its licensing requirements on chipmaking equipment, he said.

Beijing earlier said it plans to require licenses on exports of the two metals, along with their chemical compounds, starting August. China is the dominant global producer of both metals which are used in EVs, the defense industry and displays.

Gallium and germanium play a role in producing a number of compound semiconductors, which combine multiple elements to improve transmission speed and efficiency, while germanium is also used in the deposition process of making semiconductors.