China is raising its tariff on the United States to 84 percent, up from 34 percent, effective April 10 – a retaliatory move after President Donald Trump nearly doubled duties on Chinese imports.

Global markets have slumped in response to Trump imposing his latest round of tariffs, which took effect at 12:01am EST on Wednesday (04:01 GMT) and are aimed, he said, at countries that are “ripping off” the United States. Aljazeera reported.

The FTSE 100 in London opened more than 2 percent lower after Japan’s Nikkei 225 and Taiwan’s TAIEX fell more than 4 percent and nearly 6 percent, respectively, in early trade.

The tariffs hit dozens of economies, representing the biggest disruption to global trade since the 1930s.