China has warned after another round of talks on a sprawling trade dispute with Washington that any deals they produce "will not take effect" if President Donald Trump's threatened tariff hike on Chinese goods goes ahead.
The warning came after delegations led by US Commerce Secretary Wilbur Ross and China's top economic official, Vice Premier Liu He, wrapped up a meeting on Beijing's pledge to narrow its trade surplus.
Ross said at the start of the event they had discussed specific American exports China might purchase, but the talks ended with no joint statement and neither side released details.
The White House threw the meeting's status into doubt last week by renewing a threat to impose 25 per cent tariffs on $50 billion ($71.6b) of Chinese high-tech goods in response to complaints Beijing steals or pressures foreign companies to hand over technology.
The event went ahead despite that but Beijing said it reserved the right to retaliate.
Last week's announcement revived fears the conflict between the two biggest economies might dampen global growth or encourage other governments to raise their own barriers to imports.
"If the United States introduces trade sanctions including a tariff increase, all the economic and trade achievements negotiated by the two parties will not take effect," said the Chinese statement, carried by the official Xinhua News Agency.
The negotiating process should be "based on the premise" of not fighting a "trade war", the statement said.
The American Embassy in Beijing didn't immediately respond to a request for comment.
Trump is pressing Beijing to narrow its politically volatile trade surplus with the United States, which reached a record US$375.2b last year.
Tensions eased after China promised on May 19 to "significantly increase" purchases of farm goods, energy and other products and services following the last round of talks in Washington.
US Treasury Secretary Steven Mnuchin said the dispute was "on hold" and the tariff hike would be postponed. That truce appeared to end with last week's surprise announcement. It said the White House also will impose curbs on Chinese investment and purchases of US high-tech goods and on visas for Chinese students.
Analysts suggested Trump might be trying to appease critics of his Administration's deal to allow Chinese telecom equipment giant ZTE to stay in business.
They said those political pressures mean the technology-related tariff hikes are likely to go ahead. Members of Congress criticised the agreement to lift a ban on sales of US components to ZTE, which admitted violating rules on exports to Iran and North Korea.
In exchange, the company is to remove its management team, hire American compliance officers and pay a fine.
Trump has threatened to raise tariffs on a total of up to US$150b of Chinese goods. Last week's announcement gave no indication whether the other increases might also go ahead.
China has threatened to retaliate by raising import duties on a US$50b list of American goods including soybeans, small aircraft, whiskey, electric vehicles and orange juice.
It criticised the announcement but refrained from repeating its earlier threat. Beijing has resisted US pressure to commit to a firm target of narrowing its annual surplus with the United States by US$200b.
Private sector analysts say while Beijing is willing to compromise on its trade surplus, it will resist changes that might threaten plans to transform China into a global technology competitor.
Ross was accompanied by agriculture, treasury and trade officials for the meeting at the Diaoyutai State Guesthouse, a leafy compound on Beijing's west side. Liu's delegation included China's central bank governor and commerce minister.
Ross and Liu held a working dinner ahead of their talks.
"Our meetings so far have been friendly and frank, and covered some useful topics about specific export items," said Ross at the opening of today's meeting.
The US pressure over technology policy reflects growing American concern about China's status as a potential competitor and complaints Beijing improperly subsidises its fledgling industries and shields them from competition.
Foreign governments and businesses cite strategic plans such as "Made in China 2025", which calls for state-led efforts to create Chinese industry leaders in areas from robots to electric cars to computer chips.
Trade analysts had warned Ross' hand might be weakened by the Trump Administration's decision on Friday to go ahead with tariffs on steel and aluminum imports from Canada, Europe and Mexico.
That might alienate allies who share complaints about Chinese technology policy and a flood of low-priced steel, aluminum and other exports they say are the result of improper subsidies and hurt foreign competitors.