Speaking to reporters before returning to Beijing, Liu said "negotiations have not broken down. Quite the opposite: I think they are normal". Small setbacks in bilateral negotiations were inevitable, he added.
"We are cautiously optimistic about the future," said Liu, who described recent meetings as "frank and constructive". Admitting that Beijing and Washington still had differences, he said: "We have to go little by little. It's like running a marathon: it gets harder as you reach the last kilometres."
Liu said China believed that tariffs were the main trigger to trade confrontations and to reach an agreement all tariffs should be eliminated.
A major sticking point was that the US expected the Asian giant to commit to purchasing and importing a higher volume of US products. "This is a very serious matter," Liu said. "We have made it very clear that we cannot make concessions on issues of principle."
Liu addressed the media hours after the US on Friday increased tariffs to 25 per cent from 10 per cent on Chinese products worth $200 billion. China said it would take "the necessary counter-measures".
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)