Donald Trump has threatened to raise tariffs on all Chinese imports to 25 per cent, sharply ratcheting up pressure on Beijing to make concessions in trade talks and causing China’s stock markets to  tumble  6 per cent in morning trade. 

The US president made the threat in a pair of tweets on Sunday just a few days ahead of a make-or-break round of trade negotiations scheduled to begin on Wednesday. 

China’s CSI 300 index of major Shanghai- and Shenzhen-listed stocks on Monday tumbled as much as 6.1 per cent before pulling back to be down 5.5 per cent, putting the benchmark on track for its worst day since February 2016. S&P 500 futures fell as much as 2.1 per cent while in Europe futures tipped Frankfurt’s Xtera Dax index to drop 1.5 per cent at the open.