US President Trump unexpectedly announced on Thursday that he will impose new tariffs on $300 billion worth of Chinese imports, effectively taxing every product that Americans buy from China.

The president acted one day after Treasury Secretary Steven Mnuchin and U.S. Trade Representative Robert E. Lighthizer wrapped up two days of talks in Shanghai aimed at a comprehensive trade deal.

“The U.S. will start, on September 1, putting a small additional Tariff of 10% on the remaining 300 Billion Dollars of goods and products coming from China into our Country. This does not include the 250 Billion Dollars already Tariffed at 25%,” the president tweeted.

The 10% tariff will apply to rough and polished diamonds, rough and polished “synthetic gemstones” as well as “Jewelley articles of precious or semiprecious stones” coming into the US from China.