US President Donald Trump says he has instructed US trade officials to consider $US100 billion ($A130 billion) in additional tariffs against China, upping the ante in a high-stakes trade confrontation between the world's two biggest economies.
The further tariffs were being considered "in light of China's unfair retaliation" against earlier US trade actions, which included a proposed $50 billion of tariffs on Chinese goods, Trump said in a White House statement on Thursday.
Financial markets, unsettled for days by the trade fight and Trump's management of it, whipsawed again on the new threat. After a bullish regular trading day, US equity futures sold off sharply in after-market-hours trading.
S&P 500 e-mini futures traded down 1.3 per cent, with similar moves in Dow and Nasdaq futures . In the currency markets, the US dollar fell against the Japanese yen.
"The hastily crafted policy like we have seen from Trump over the last two, three days and now tonight ... is dangerous," said Doug Kass, who runs hedge fund Seabreeze Partners Management Inc.
"Our president is going to make market volatility and economic uncertainty great again."
In his statement, Trump said the US Trade Representative had determined that China "has repeatedly engaged in practices to unfairly obtain America's intellectual property."
Earlier this week, the Trump administration proposed 25 per cent tariffs on 1300 Chinese industrial and other products. China shot back with a list of similar proposed duties on American imports, including soybeans, planes, cars, beef and chemicals.
"Rather than remedy its misconduct, China has chosen to harm our farmers and manufacturers," the Republican president said.
The tit-for-tat tariff announcements have stirred fears that the two countries will spiral into a trade war that will crush global growth. Republican representatives from Western and Midwestern states have voiced worries about a big hit to US farming exporters.
On the new tariff threat, Republican Senator Ben Sasse said in a statement: "Hopefully the president is just blowing off steam again but, if he's even half-serious, this is nuts.
"China is guilty of many things, but the president has no actual plan to win right now. He's threatening to light American agriculture on fire. Let's absolutely take on Chinese bad behaviour, but with a plan that punishes them instead of us. This is the dumbest possible way to do this," said the lawmaker from the farm-belt state of Nebraska.
White House officials have suggested throughout the week that talks with the Chinese could help resolve trade issues between the two countries. China ran a $US375 billion goods trade surplus with the US in 2017. Trump has demanded that China cut the trade gap by $US100 billion.
A senior US official who requested anonymity told Reuters no formal negotiating sessions had yet been set, but the US was willing to negotiate.
US President Donald J. Trump. Source: AAP (SAUDI PRESS AGENCY)
The US tariffs are aimed at forcing changes to Chinese government policies designed to transfer US intellectual property to Chinese companies.
The USTR's "Section 301" investigation authorising the tariffs alleges China has systematically sought to misappropriate US intellectual property through joint venture requirements that often cannot be negotiated without technology transfers, something China denies.
