In retaliation to China's move, US President Donald Trump increased tariffs on the $250 billion Chinese goods from 25 percent to 30 percent (starting 1 October) and those on the remaining goods worth $300 billion to 15 percent from the earlier 10 percent (starting 1 September).

In a series of tweets, Trump also accused China and "many other countries" of having been taking advantage of the US in trade.

The Office of the US Trade Representative in a statement on Friday (Washington time) called Beijing's planned tariffs on Amercian goods as "unjustified." It also said it would publish "as soon as possible any additional details" in the Federal Register on the new duties Trump announced in his tweets.

Further, in an earlier tweet, Trump "ordered" the US manufacturers to find alternatives to China for their operations. "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," he said.

The tweet led to a fall in American stock indices. The Nasdaq Composite closed 3 percent lower to end at 7,751.77, Dow Jones Industrial Average dropped 623.34 points or 2.4 percent at 25,628.90, while the S&P 500 index fell 2.6 percent at close at 2,847.11. Stocks of companies with major operations in China, like Apple Inc, saw their prices fall.

With the intensifying US-China trade war, that has been going on with no hopes of a resolution for over a year, the outlook for the global economy remains dim.