On the US list were Chinese electric and conventional cars, flat panel TV screens, trains, robots, commercial ovens, snowblowers, lithium batteries, aerospace and engineering parts, among many high technology and value-added products.

The US Trade Representative's Office said the tariffs were being imposed "in response to China’s policies that coerce American companies into transferring their technology and intellectual property to domestic Chinese enterprises".

"As the Chinese saying goes, it is only polite to reciprocate," China's Washington embassy said.

China's commerce ministry said it would hit back with "equal scale and equal intensity", and outlined that 106 US products in 14 categories would attract an extra 25 per cent tariff. US beef, corn and cotton were also on the list.

Hours after Beijing's latest tariffs, President Trump took to Twitter to deny that the United States was in a trade war with China.

"We are not in a trade war with China, that war was lost many years ago by the foolish, or incompetent, people who represented the US," Trump wrote in a post.

The escalation in threats on Wednesday came despite US officials seeking last week to calm financial markets and downplay concerns of a trade war, claiming Chinese negotiators may agree to the trade concessions Mr Trump wants thus averting the imposition of tariffs.

Instead, the Chinese retaliation list, published swiftly on Wednesday afternoon before a two-day Chinese public holiday for Tomb Sweeping, has returned fire on Mr Trump's tough negotiating tactics.

The brinksmanship may still lead to a breakthrough in the coming days, with Chinese President Xi Jinping scheduled to give a major speech on "new opening up measures China will take" at the Boao Forum on Monday, according to Foreign Minister Wang Yi.

An editorial in the hawkish Global Times said tariffs on US soybeans and corn would hurt US farmers and increase political pressure on Mr Trump, and encouraged higher tariffs on US car makers such as General Motors selling into the world's largest car market.

There will be a 60-day delay before the US tariffs take effect, while China said its timetable for the proposed new tariffs would depend on when the US acted.

Chinese vice-minister of commerce, Wang Shouwen, said: "We want to have negotiations on the basis of equality and mutual respect. If anyone wants to fight we will be there with him. If they want to negotiate, the door is open."

Mr Trump has criticised China for its large trade surplus with the US, and has demanded a $US100 billion reduction in the trade imbalance, but the tariffs appear to instead target China's innovation program.

China will lodge a complaint with the World Trade Organisation.

Mr Wang said it was "not possible" to immediately reduce the trade imbalance by $US100 billion as Mr Trump had demanded, because it required structural change in the relationship.

China hoped the US could relax its export restrictions on technology products, increase the savings rates and increase services trade.

There are fears a trade war between the US and China will unravel the global trading system and impact on economic growth trade-reliant countries such as Australia.

In retaliation for Trump's earlier steel and aluminium tariffs, China on Monday imposed tariffs on $3 billion worth of US products, including pork, wine and citrus. But Wednesday's retaliation round will be far more costly to US exporters.

Chinese premier Li Keqiang said last month that China would improve conditions for foreign companies, bringing down overall tariffs for imports, and open up manufacturing to foreign investors with no requirement for technology transfer.

Mr Li said the trade imbalance could be solved if the US eased restrictions on high technology exports to China.

Instead, Washington has warned allies including Australia that Chinese technology companies present a national security risk, in areas including 5G.