Despite the changes, the new tariffs still will cover about US$200 billion worth of additional Chinese goods, as part of an intensifying trade dispute between the world's two largest economies.
A White House statement said tariffs would start at 10 percent and go into effect in a week, on September 24, before kicking into full gear at 25 percent at the start of the new calendar year.
If the administration pursues what it calls "phase three" of the tariff strategy, it would raise the total value of affected Chinese goods to $517 billion - covering almost everything China sells the United States.
Earlier Monday, White House chief economic adviser Larry Kudlow said at the Economic Club of New York, "We are ready to negotiate and talk with China any time that they are ready for serious and substantive negotiations" to reduce trade barriers.
A second administration official told CNBC that the cost of these tariffs would amount to 10 percent of all imports targeted, down from earlier estimates of 25 percent.
The tough talk follows reports China is deliberately reducing exports to the USA by slowing down customs approvals and stepping up environmental and other inspections.
China's Foreign Ministry reiterated that the escalation of the trade conflict was not in anyone's interest. Apple Inc. said last month the proposed duties on US$200 billion cover a wide range of products used in its USA operations. "My Administration will not remain idle when those interests are under attack", Trump said in a statement. The levies focused on industrial products, not on things Americans buy at the mall or via Amazon.
At the same time, the administration said it is still open to negotiations with China. But Trump quickly backed away from the truce.
In a pair of tweets, Trump continued to make the case that tariffs largely harm the countries that are taxed, saying the impact on the USA economy has been "almost unnoticeable".
By expanding the list to $200 billion worth of Chinese imports, Trump risks spreading the pain to ordinary Americans. I have a lot of respect for China.
Trump's tariffs on China raise costs and create uncertainty for companies that have built supply chains that span the Pacific Ocean.
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