President Donald Trump said China had refused to change the unfair practices that hurt US businesses and workers

US President Donald Trump on Tuesday accused China of seeking to influence knife-edge midterm congressional elections by taking aim at his political base in the economic giants' rapidly escalating trade war.

The allegation raised the temperature in the escalating dispute after Trump pulled the trigger late Monday on 10 percent tariffs against another $200 billion in Chinese goods from next week, with a threat of more tariffs on another $267 billion.

Beijing responded by announcing new tariffs on $60 billion of US imports to take effect at the same time.

In a combative series of tweets, Trump, whose Republicans fear losing control of Congress in November, accused China of targeting retaliatory trade measures for political effect.

Accusations of election meddling are especially sensitive, given the political maelstrom over Russia's alleged intervention to support Trump in the 2016 presidential vote.

"China has openly stated that they are actively trying to impact and change our election by attacking our farmers, ranchers and industrial workers because of their loyalty to me," Trump wrote.

"China has been taking advantage of the United States on Trade for many years. They also know that I am the one that knows how to stop it," he added.

"There will be great and fast economic retaliation against China if our farmers, ranchers and/or industrial workers are targeted!"

It was unclear to which open statements by China -- if any -- Trump was referring.

However, China and other US trading partners have targeted their retaliation to inflict pain in politically sensitive areas, including in areas that Democrats hope take from Republicans in November.

Recent NBC News/Marist polling has also found the trade war is unpopular in six states: Illinois, Indiana, Missouri, Pennsylvania, Tennessee and Texas.

- Tearing up the rulebook -

Trump believes that his tearing up of the international trade rulebook is long overdue. His promise to end what he says are grossly skewed Chinese trade relations was a key plank of his election.

At a news conference on Monday, Trump again said the United States had been "ripped off" by China.

"They rebuilt their country with tremendous amounts of money pouring out of the United States. I have changed that around," Trump said during a news conference with Polish President Andrzej Duda.

"Our country has been abused and taken advantage of by virtually every country that it does business with. And we're just not letting that happen anymore."

Washington accuses China in particular of seeking global industrial dominance through industrial espionage and forced transfers of technology from foreign companies, state-sponsored corporate acquisitions, illicit market interventions, subsidies and dumping.

Administration officials told reporters this week that China had been "obdurate" in refusing to address American grievances.

Once the new round of tariffs takes effect on September 24, punitive duties will be in place on $250 billion in goods the US buys from China -- its largest source of imports.

This latest round of imports will face 10 percent tariffs through the end of the year, when the rate jumps to 25 percent.

Trump has warned further retaliation from China will see the US put duties on all US imports from the Asian economy.

- Smartwatches spared -

The new taxes will hit a broad swath of products, including billions in Chinese-made voice data receivers, computer memory modules, data processors, and accessories for office equipment such as copiers and banknote dispensers -- instantly making widely used goods more expensive.

However, officials told reporters the initial list announced in July was reduced by 300 products following complaints from US industry.

The products spared included consumer electronics like smartwatches and Bluetooth devices, child safety products such as high chairs, car seats and playpens, and certain health and safety products such as bicycle helmets.

The removal of smartwatches and wireless headphones represents a win for tech giant Apple, which had warned the tariffs would hit its Apple Watch and Airpods product lines.

- Blow to consumers -

The escalating confrontation initially shook up global stock markets, but Wall Street closed up solidly with investors relieved Trump's measures had not been harsher.

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