The U.S. has been importing about three million parcels a day with little customs inspection, raising concerns about the ease of sending fentanyl.

The U.S. Postal Service said it would stop accepting parcels from China and Hong Kong, cutting off a service that is popular with online vendors in China. The Postal Service said it is suspending inbound packages from China Post and Hong Kong Post until further notice and that the change wouldn’t affect delivery of letters.

The US Postal Service (USPS) says it has temporarily stopped accepting parcels from mainland China and Hong Kong. Letters will not be affected by the suspension, according to a statement on the company's website.

Beijing has made its decision. After days of warning of counter measures and urging Washington to enter negotiations and "meet China halfway", it has decided to hit back – or at least threaten to retaliate with its own tariffs.

Trump’s 10% tariffs on China take effect, triggering retaliation Beijing imposes some counter levies, takes US to WTO Google, Tommy Hilfiger, Calvin Klein owner among China targets China tariffs come even as Trump delays duties on Canada,

China announced a wide range of measures on Tuesday targeting U.S. businesses including Google, farm equipment makers and the owner of fashion brand Calvin Klein, minutes after new U.S. tariffs on Chinese goods took effect.