A USA-China trade war may start. Stock markets in Asia fell because people are worried. President Donald Trump wants to put tariffs on Chinese goods. A tariff is a tax on imports (things bought from other countries). Mr Trump wants to put tariffs on $60 billion of Chinese imports. China said it would do the same.

If the USA uses tariffs, China will hit back. Then the U.S. will hit back further. A researcher said: "This can turn ugly…very quickly." Trump wants to protect U.S. workers. He is not happy because the USA buys $385 billion more goods from China than China buys from the USA. Mr Trump wants to cut this imbalance.