Washington already imposed 25 percent tariffs on $34 billion in Chinese products on July 6.
The US and China have been trying to restart high-level talks that broke off after Trump followed through on his tariff threats. They will take effect on August 23.
The office said the move is part of the US response to China's unfair trade practices related to the forced transfer of American technology and intellectual property.
China's exports surged more than expected in July despite US duties and its closely watched surplus with the United States remained near record highs, as the world's two major economic powers ramp up a bitter dispute that some fear could derail global growth.
The 25% import taxes will apply to about $16bn (£12b.3bn) worth in annual imports, covering about 280 items, including chemicals and machinery.
"There is no off-ramp, and Trump has given China little wiggle room to save face and come to the bargaining table", he said.
All in all, China's trade surplus with the USA shrank to $28.08 billion in July against $28.97 billion in the previous month. Washington has long criticized China's trade surplus with the United States and has demanded Beijing cut it.
It has not yet given a date for its previously announced retaliatory tariffs on $16 billion in USA goods, which will target commodities such as crude oil, natural gas, coal and some refined oil products. There is a mandatory 60-day comment period for industries to ask for exemptions from the tariffs.
Of more direct effect in the Sino-U.S. trade war, China's surplus with the United States shrank only marginally to $28.09 billion last month from a record $28.97 billion in June. Chinese data on Wednesday showed exports to the United States rose 13.3% in July to $41.5 billion against a year ago.
The trade balance between the two countries, which is at the center of the tariffs tussle, continued to be in favor of China.
August 3: China announces that the country will impose tariffs of various rates on another $60 billion worth of USA goods if Trump moves forward with his latest threat. The administration has said that it will pursue tariffs on an additional $200 billion if China continues to respond with retaliatory tariffs rather than reform of its own trade practice.
It will be the second time the USA slaps duties on Chinese goods in about the past month, despite complaints by American companies that such moves will raise business costs and eventually consumer prices.