Here are the reasons for Trump's economic war with China

On Friday the US president 'hereby ordered' companies to halt business with China, among other attacks - how did we get here?

Even by Donald Trump's standards his Twitter rant attacking China on Friday was extraordinary. In a series of outbursts Trump "hereby ordered" US companies to stop doing business with China, accused the country of killing 100,000 Americans a year with imported fentanyl and stealing hundred of billions in intellectual property.

The attack marked a new low in Sino-US relations and looks certain to escalate a trade war already worrying investors, manufacturers and economists who are concerned that the dispute between the two economic superpowers could trigger a recession.

Related: Trump escalates attacks on China and threatens to raise tariffs