China hits back with export controls, Canada and Mexico remain under threat. USPS closes then reopens "di minimis" small package loophole

After a 10 percent tariff on Chinese products took effect on Tuesday, China announced retaliatory measures, including tariffs and an investigation of Google.

The world’s two largest economies did not cut a deal to avert sweeping U.S. tariffs, which came into effect after midnight. Beijing immediately retaliated.