Major stock markets across Asia Pacific region sank Monday amid mounting fears of a renewed trade war between the world’s two largest economies, after US President Donald Trump threatened to impose new triple-digit tariffs on Chinese imports.

Trump’s threat followed Beijing’s tightening of its control on rare earths, a group of critical minerals essential in the production of a wide range of electronics, automobiles and semiconductors. China dominates the global rare earth supply chain.

Those restrictions came after the US introduced a slew of its own export controls targeting China in late September, despite the two sides seemingly making progress in trade talks over the summer.

China’s sweeping new restrictions, some of which won’t take effect until November, could deal a huge blow to East Asian economies, such as Japan, South Korea and Taiwan, which play critical roles in the global tech and artificial intelligence supply chain, as well as the auto industries.