Over the first six months of the year the surplus climbed to $133.8 billion as total two-way trade continued to expand despite the face-off.
Pressed on the possible negative impact of multiple trade disputes on the USA economy, Mnuchin said the Trump administration was keeping a watchful eye.
Last week, the United States and China introduced tariffs of 25 percent on $34 billion of each other's exports.
Even so, the US dollar hit a six-month high against the safe-haven Japanese yen as currency traders put trade worries aside and focused on Labor Department data that showed producer prices rising more than expected.
Earlier this week Donald Trump proposed a 10% tariff on $200bn of Chinese goods entering the United States, saying that tariffs already in place on steel and aluminium imports and $34bn of goods had failed to force significant reforms by Beijing.
"Concerns over trade and trade wars are really having an adverse effect, less so on the USA markets than the worldwide markets, but it is certainly taking a bite".
China's trade imbalance is at the heart of US President Donald Trump's anger at what he describes as Beijing's unfair trade practices that are hurting American companies and destroying jobs.
As the world's largest exporter, China has threatened retaliatory action against the tariffs and pledged that it would lodge a complaint with the World Trade Organization.
The June figures may have received a boost from United States and Chinese traders who rushed to fill orders for soybeans, ball bearings and other goods in both directions before threatened tariff hikes took effect.
China's commerce ministry confirmed last month that Chinese exporters were front-loading exports to the U.S.to get ahead of expected tariffs - a situation that could exacerbate any slowdown in shipments toward the year-end.
South Korea, Asia's fourth-largest economy, warned on Thursday that components and materials used in home appliances, computers and communications devices could be caught in the crossfire of the trade war.
Exports rose 11.3 per cent over a year earlier to $216.7 billion, down from May's 12.6 per cent growth, customs data showed Friday.
Imports grew 14.1 percent in June, customs said, missing analysts' forecast of a 20.8 percent growth, and compared with a 26 percent rise in May.
A spokesman for the hotel told The Global Times: "Our boss was really angry about the endless tariffs the United States planned to..."
China said the two sides were not discussing restarting trade negotiations.
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