China US trade war - US market tumbles

US markets have fallen on the back of the escalating trade row with China. China has unveiled retaliatory tariffs on more than 100 US goods including a key commodity - soybeans - as well as aircraft and cars. The measures come after the Trump administration published a list of 1300 Chinese items to be subject to an equivalent charge. Our correspondent in Washington D.C., Daniel Ryntjes, speaks to Guyon Espiner.