China has accused the US of bullying and warned it would hit back after the Trump administration raised the stakes in their trade dispute, threatening 10% tariffs on $200 billion of Chinese goods.
China's commerce ministry said it was "shocked" and would complain to the World Trade Organisation, but did not immediately say how it would retaliate.
In a statement, it called the US actions "completely unacceptable".
The foreign ministry described Washington's threats as "typical bullying" and said China needed to counter-attack to protect its interests.
"This is a fight between unilateralism and multilateralism, protectionism and free trade, might and rules," foreign ministry spokeswoman Hua Chunying told a regular briefing today.
Beijing has said it would hit back against Washington's escalating tariff measures, including through "qualitative measures".
This is a threat that US businesses in China fear could mean anything from stepped-up inspections to delays in investment approvals and even consumer boycotts.
China could also limit visits to the US by Chinese tourists, a business state media said is worth $115 billion, or shed some of its US Treasury holdings, analysts said.
The $200 billion far exceeds the total value of goods China imports from the US, which means Beijing may need to think of creative ways to respond to such US measures.
US officials yesterday issued a list of thousands of Chinese imports the Trump administration wants to hit with the new tariffs.
The list includes hundreds of food products as well as tobacco, chemicals, coal, steel and aluminium, prompting criticism from some US industry groups.
It also includes consumer goods ranging from car tyres, furniture, wood products, handbags and suitcases, to dog and cat food, baseball gloves, carpets, doors, bicycles, skis, golf bags, toilet paper and beauty products.
"For over a year, the Trump administration has patiently urged China to stop its unfair practices, open its market, and engage in true market competition," US Trade Representative Robert Lighthizer said as he announced the proposed tariffs.
"Rather than address our legitimate concerns, China has begun to retaliate against US products. There is no justification for such action," he said in a statement.
Last week, Washington imposed 25% tariffs on $34 billion of Chinese imports, and Beijing responded immediately with matching tariffs on the same amount of US exports to China.
Each side is planning tariffs on a further $16 billion in goods that would bring the totals to $50 billion.
Investors fear an escalating Sino-US trade war could hit global growth and damage sentiment and markets in Europe and Asia suffered losses this morning.
US President Donald Trump has said he may ultimately impose tariffs on more than $500 billion worth of Chinese goods - roughly the total amount of US imports from China last year.
The new list published yesterday targets many more consumer goods than those covered under the tariffs imposed last week, raising the direct threat to consumers and retail firms and increasing the stakes for lawmakers in Mr Trump's Republican party facing elections in November.
The list is subject to a two-month public comment period before taking effect.
Some US business groups and lawmakers from Trump's own Republican Party were critical of the escalating tariffs.
Senate Finance Committee Chairman Orrin Hatch said the announcement "appears reckless and is not a targeted approach".
The US Chamber of Commerce has supported Trump's domestic tax cuts and efforts to reduce regulation of businesses, but does not back Trump's aggressive tariff policies.
"Tariffs are taxes, plain and simple. Imposing taxes on another $200 billion worth of products will raise the costs of every day goods for American families, farmers, ranchers, workers, and job creators. It will also result in retaliatory tariffs, further hurting American workers," a Chamber spokeswoman said.
President Trump has been following through on pledges he made during his presidential campaign to get tough on China, which he accuses of unfair trade practices including theft of intellectual property and forced technology transfer that have led to a $375 billion US trade deficit with China.
China's exports have mushroomed since it joined the World Trade Organisation in 2001, making it the world's second-largest economy and prompting widening criticism in recent years from trading partners that it has unfairly used global trade rules to its advantage.
As its dispute with Washington deepened, Beijing has been calling on other countries to support global free trade and has talked up efforts to ease investment rules.
During a visit to Germany this week by Chinese Premier Li Keqiang, the countries signed business deals worth more than $23 billion.
"China stands in line with the international community on the correct side of history to together protect the rules of the multilateral trade order," foreign ministry spokeswoman Hua said.