The hike in tariffs, from 34%, came after US President Donald Trump's 104% tariff on Chinese goods came into force on Wednesday - they were later increased to 125%. Trump said the 21% rise was "based on the lack of respect" China had shown, and that it would be "effective immediately".

The de minimis exception, which has allowed businesses to import low-value goods without duties from China and Hong Kong, has expired as of 12:01AM ET today as part of President Trump’s executive order signed last month.