Trump, who has boasted that trade wars are "easy to win", has threatened to ramp up the pressure and slap tariffs on virtually all of China's exports to the United States if Beijing does not back down and take steps to reduce the $335 billion USA trade deficit with that country. After Liu visited Washington later that month, the nations released a joint statement pledging to reduce the USA trade deficit with China, among other things.
U.S. president Donald Trump has threatened to target all $500bn of Chinese imports.
The tranche of 25 per cent tariffs - which covers 279 products including electronic parts, plastics, chemicals, batteries, tractors and railway cars - follows $US34 billion worth of tariffs announced by the United States government in July.
Sales to the USA rose by 13.3%, while China's surplus with the States shrank marginally to $28.1bn (£21.7bn) last month from a record $29bn (£22.4bn) in June.
The Trump administration has finalized a new round of 25 percent tariffs on an additional $16 billion in Chinese imports. However, analysts still expect a less favourable trade balance for China in coming months given it's early days in the tariff brawl.
After a strong start to the year, growth in the world's second-largest economy cooled slightly in the second quarter, partly hit by the government's years-long efforts to tackle debt risks.
Several industry bodies in the United States representing agribusiness, retail and technology have said the Trump administration's tariffs are hurting them and will cause long-term damage to farmers, manufacturers and consumers.
The duties are part of a broader round of tariffs on $50bn worth of goods the United States announced in March.
China has responded with retaliatory tariffs of its own.
The surplus with the United States was higher than China's overall trade surplus in July, which was $28.05 billion, indicating China ran a net trade deficit with the world excluding the U.S.
"Although this may for a moment bring preening with delight, it will make it hard to resolve economic imbalances or out of kilter politics and other deep-rooted problems".
No date yet for the previously announced retaliatory tariffs on $16 billion in US goods, which will largely target commodities. The retaliatory tariffs hit USA industries in areas of the US where President Trump has received significant support.
USTR said there were 279 new goods to be targeted in the dispute over China's policies promoting theft of American technology.