US President Donald Trump announced on Thursday that an additional 10% tariff will be laid onto $300 billion worth of Chinese imports.

The tariffs will come into force from September 1 and are not part of the $250 billion worth of Chinese goods that were tariffed at 25% back in May.

"Our representatives have just returned from China where they had constructive talks having to do with a future Trade Deal. We thought we had a deal with China three months ago, but sadly, China decided to renegotiate the deal prior to signing," Trump tweeted.

"More recently, China agreed to buy agriculture product[s] from the US in large quantities, but did not do so.

"Trade talks are continuing, and during the talks the U.S. will start, on September 1st, putting a small additional Tariff of 10% on the remaining 300 Billion Dollars of goods and products coming from China into our Country. This does not include the [$250 billion] already tariffed at 25%."

See also: Taiwan profits from America's trade war with China

The tariffs could result in smartphones and laptops becoming more expensive, given that many tech companies use components manufactured in China.

A report by the Consumer Technology Association published in June found that the new set of tariffs against Chinese imported goods could raise prices on new laptops by 17% in the US.

The new set of tariffs mark the continuation of the US-China trade war, and also brings an end to the run of positive trade talks that commenced in June when the president met with China's President, Xi Jinping, at the G20 Summit in Osaka.

The US first began enforcing tariffs and investment restrictions on Chinese companies in March last year, with Trump stating at the time that an investigation by US Trade Representative Robert Lighthizer had concluded China was using foreign ownership restrictions to require technology transfers from US companies to Chinese organisations, as well as conducting espionage to acquire intellectual property and confidential business information.

By June last year, the US and China had both levied tit-for-tat tariffs on $34 billion worth of goods. Two months later, the US also began collecting a 25% import duty on 279 Chinese goods valued at $16 billion, composed mostly of industrial products including steam turbines and iron girders.

Come May, Trump made good on his pledge to add a 25% tariffs to $200 billion worth of products, and later that month, added another 25% tariff to a separate set of Chinese goods valued at $50 billion.

The Office of the US Trade Representative released a list in May of more than 3,800 import codes for products that will be subject to new tariffs.

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