US President Donald Trump took to Twitter to 'order' American companies to close their operations in China, after China unveiled retaliatory tariffs against about $75 billion worth of US goods.

Wall Street's three main indexes lost about 1%  after President Donald Trump said US companies should "immediately start looking for an alternative to China".

China's commerce ministry said in a statement it would impose additional tariffs of 5% or 10% on a total of 5,078 products originating from the United States that include agricultural products, crude oil, small aircraft and cars. 

Tariffs on some products would take effect on September 1st and others on December 15th.

That mirrors a plan by the US to impose 10% tariffs on $300 billion of Chinese goods, with the new tariffs coming in on a phased basis on the same September and December dates.

The announcement came as leaders of the G7 nations prepared to meet in France.

Donald Trump sanctioned the new tariffs earlier this month. 

China responded by halting purchases of agricultural goods and allowed the yuan to weaken, leading Washington to brand it a currency manipulator.

The US president said in a tweet, that he was ordering US companies to find alternatives to China.

President Trump cannot compel US companies to abandon China and he gave no detail on how he might proceed with any such order, although he said he would be offering a response later on Friday to tariffs on US products announced by China.

"Our great American companies are hereby ordered to immediately start looking for an alternative to China, including bringing your companies HOME and making your products in the USA," Trump said on Twitter. "We don't need China and, frankly,would be far better off without them."