The Commerce Ministry criticized Trump's order to prepare tariffs on $200 billion of Chinese goods as blackmail.
China warned it will take "qualitative" and "quantitative" measures if the US government publishes an additional list of tariffs on its products.
It gave no details.
In the first round of penalties announced by both nations, to take effect July 6, the US plans to impose tariffs of 25 percent on $34 billion of Chinese imports, such as construction machinery, aerospace, and power generation equipment. It also scrapped agreements to narrow China's trade surplus with the United States by purchasing more American farm goods, natural gas and other products.
Meanwhile, markets have responded poorly to Trump's tariffs play, dipping repeatedly with each new tariff announcement.
The Hong Kong bourse fell 3.1 percent, while Shanghai was down 3.8 percent, its lowest level since mid-2016.
"China apparently has no intention of changing its unfair practices related to the acquisition of American intellectual property and technology", Trump said in the statement.
"We don't want a trade war, but we're not afraid of a trade war, " ministry spokesman Geng Shuang said. China threatened retaliatory tariffs of $50 billion this year when Trump first ordered his officials to consider an additional $50 billion.
The declines in the USA markets followed a global rout.
In Beijing, China's Commerce Ministry responded swiftly to Trump's latest threat, warning that if the U.S. imposed fresh tariffs, China would have to adopt "comprehensive measures combining quantity and quality to make a strong countermeasure".
Beyonce, Jay-Z Surprise Fans With 'Everything Is Love' Album Release
Everything is Love suggests that the two have worked things out between them, and are very much a team, a family, moving forward. Jay noted that those recording sessions birthed Beyonce's 2016 " Lemonade " album and later Jay-Z's 2017 "4:44" album .
However, "history shows that there are various other measures [China] could take to inflict pain on United States companies, especially those present in China, including scaled up health, safety and tax checks, delaying the imports of goods, and boycotts of USA goods", he said.
Meanwhile, the state-backed tabloid Global Times said in an editorial that Trump was gambling with the "US public interest" by escalating the trade row with China.
Economists warn Washington might be undercutting its negotiating position by alienating potential allies.
"Investors are anxious the USA may impose further restrictions on Chinese tech and Internet products and cause greater uncertainty for the domestic economy", Zhang Gang, Shanghai-based strategist with Central China Securities Co, told Bloomberg News. Tokyo's Nikkei 225 retreated 1.8 percent to 22,278.48 and Seoul's Kospi gave up 1.5 percent to 2,340.11.
"The trade relationship between the United States and China must be much more equitable", the president said in explaining his decision.
Canada and Mexico, both members with Washington of the North American Free Trade Agreement (NAFTA), have not been spared the USA offensive on steel and aluminium and are threatening their own reprisals.
The White House was not pleased.
Later on Friday, China announced its own tariffs on American goods, including a wide range of seafood and agricultural products, many cars and trucks, petrochemicals and an array of medical equipment.
Trump's proposed new tariffs would amount to the latest round of punitive steps in an escalating dispute between the world's two largest economies.
The move quickly drew praise from former Trump senior adviser Steve Bannon, who told The Associated Press: "President Trump told China and the world tonight that America will not back down when it comes to economic aggression".