“These are unfortunate developments,” the Republican Senator from Montana said on Monday. Daines is a member of two of the most powerful committees in the US Senate: the Foreign Relations and Finance Committees.

“The escalation on both sides here is something I was hoping would not happen,” he added.

Weeks after US President Donald Trump and Chinese leader Xi Jinping agreed to easing of tensions during their summit in Beijing, both sides have resumed retaliatory actions, highlighting the fragility of the truce and the persistent distrust between the world’s two largest economies.Last week, China targeted two US rare earth giants – MP Materials and USA Rare Earths – along with eight other American firms, which were hit with stringent export controls, and barred 46 US firms from government procurement.

What are rare earths, and why is China’s dominance facing global pushback

The regulations prohibit exporters from supplying dual-use goods to the 10 companies and ban any organisation or individual worldwide from transferring China-origin dual-use items to them, extending the restrictions beyond China’s borders.