Chinese Vice Premier Liu He, centre, poses with U.S. Trade Representative Robert Lighthizer, right, and Treasury Secretary Steven Mnuchin, for photos before holding talks at the Xijiao Conference Center in Shanghai. Picture: Ng Han Guan/AP

Washington - US President Donald Trump has announced that he will hike tariffs on some 300 billion dollars' worth of Chinese goods to 10 per cent starting on September 1.

The measures will come on top of the 25-per-cent tariffs that have been imposed on 250 billion dollars' worth of Chinese products coming into the US.

The announcement comes on the heels of talks between the world's two largest economies in Shanghai this week. The negotiations did not appear to yield any significant progress, though Trump said "positive dialogue" between the sides will continue.

"We look forward to continuing our positive dialogue with China on a comprehensive Trade Deal, and feel that the future between our two countries will be a very bright one!" the president wrote on Twitter.

In announcing the new tariffs, Trump said China had pledged to increase purchases of US agricultural products, but did not, and also alleged Beijing reneged on a promise to stop the sale of Fentanyl to the US.