Chinese and US negotiators have adjourned trade talks in Beijing with US treasury secretary Steven Mnuchin saying they were "constructive".
Neither side gave any details on whether the talks made progress on issues preventing them from reaching an agreement to end a wide-ranging dispute over technology and industrial policy between the world's two biggest economies.
Mr Mnuchin said he and US trade representative Robert Lighthizer had "concluded constructive trade talks".
"I look forward to welcoming China's vice premier Liu He to continue these important discussions in Washington next week," he added.
.@USTradeRep and I concluded constructive trade talks in Beijing. I look forward to welcoming China’s Vice Premier Liu He to continue these important discussions in Washington next week. #USEmbassyChina pic.twitter.com/ikfcDZ10IL— Steven Mnuchin (@stevenmnuchin1) March 29, 2019
Mr Mnuchin and Mr Lighthizer attended a working dinner with Mr Liu on Thursday night, shortly after their arrival in the Chinese capital. It was not clear when the US envoys planned to leave Beijing.
President Donald Trump expressed optimism about the talks last week, saying: "We're getting very close."
Mr Lighthizer said earlier this week that questions about details and enforcement remained to be answered.
The meetings are the latest in a rapid-fire series of exchanges seeking to end the conflict that is disrupting trade in goods from soybeans to medical equipment.
"Both teams are currently sparing no effort" on the negotiations, Chinese commerce ministry spokesman Gao Feng said during a regularly scheduled briefing.
A stumbling block appears to be Washington's insistence on an enforcement mechanism with penalties if Beijing fails to follow through on commitments, but trade analysts expect at least a preliminary accord in coming weeks or months.
The negotiations are unlikely to resolve conflicts that have troubled US-Chinese relations for two decades, including China's massive trade surplus with the US and accusations it has stolen or coerced the transfer of foreign technology for its own use.
Mr Trump raised duties last year on Chinese imports in response to companies' complaints. Last week, he said he wanted to keep in place the 25% taxes on $50 billion dollars (€44 billion) of Chinese goods that he imposed in July.
Washington followed those with 10% duties on an additional $200 billion (€178 billion). All told, the American tariffs covered roughly half of what the US buys from China.
However, Mr Trump postponed another tariff hike that had been set for March 1. That may have reduced US leverage in seeking Chinese concessions.