Chinese companies that sell products on Amazon are preparing to hike prices for the US or quit that market due to the "unprecedented blow" from President Donald Trump's tariff hikes, the head of China's largest e-commerce association said.

Trump said on Wednesday he would raise tariffs on Chinese imports to 125% from the 104% level already in effect, escalating the high-stakes confrontation between the two world's largest economies.

"This isn't just a tax issue, it's that the entire cost structure gets entirely overwhelmed," said Wang Xin, the head of the Shenzhen Cross-Border E-Commerce Association, which represents more than 3,000 Amazon sellers.

"It'll be very hard for anyone to survive in the US market," she told Reuters.

Some sellers are looking to increase prices in the US while others are looking to find new markets, Wang said.

The tariffs will severely impact China's small enterprises and manufacturers and also rapidly accelerate the country's unemployment rate, she added.