While the US has yet to confirm the tariff rollback, China's key demand since the start of negotiations has been the removal of tariffs imposed by US President Donald Trump, which today apply to some US$550 billion (S$746 billion) worth of goods, the majority of its exports to the US.
Gao stressed that equivalent cuts done at the same time by both sides would be an important condition to achieve a limited agreement that the countries agreed on last month.
Over the past couple of weeks, delegates from the US and China have had "serious and constructive" discussions in an effort to secure a deal that would end their more-than-yearlong tariff dispute, Gao added.
A spokesman for the International Monetary Fund said an interim trade deal that rolled back some tariffs had the potential to improve its economic forecasts for 2020.
Chinese officials confirmed they were thrashing out the shape of a first-stage trade deal with the USA, which will force Beijing to end a moratorium on purchases of some U.S. agricultural goods such as soya beans in exchange for Washington applying lighter tariffs on Chinese imports.More news: Lady Gaga cancels show in Las Vegas; check out more details
"Given President Trump's love of tariffs, the additional element (of tariff rollbacks) may increase the risk and prolong the phase-one negotiation", said OCBC Bank's head of Greater China research Tommy Xie.
He did not give a timeline.
In what could be another gesture to boost optimism, China's state news agency Xinhua reported late on Thursday that the Chinese customs and the ministry of agriculture are considering removing restrictions on U.S. poultry imports.
China has banned all United States poultry and eggs since January 2015 due to an avian influenza outbreak.
Share prices on Wall Street rose on Thursday, on expectations of significant progress in the trade talks.More news: Ambush on mining company convoy kills 37 in Burkina Faso
A source briefed on the talks told Reuters on Tuesday that Chinese negotiators want Washington to drop 15% tariffs on about $125 billion worth of Chinese goods that went into effect on September 1. They are also seeking relief from earlier 25% tariffs on about $250 billion of imports from machinery and semiconductors to furniture.
A person familiar with China's negotiating position said it is continuing to press Washington to "remove all tariffs as soon as possible".
United States locations for a meeting between Trump and Chinese President Xi Jinping (習近平) that had been proposed by the White House, including Iowa and Alaska, have been ruled out, a person familiar with the matter said.
Americans for Prosperity president Tim Phillips discusses Republican difficulties courting suburban voters, revenue collected from President Trump's tariffs, and US economic growth. Trump remains upbeat on the chances Beijing and Washington will seal the mini-deal he announced earlier this month - marking a cooling-off period in the two nations' damaging trade war.
Dozens of venues have been suggested for the meeting, which had originally been scheduled to take place on the sidelines of a now-canceled mid-November summit of Asia-Pacific leaders in Chile, the official said. A location for an upcoming meeting has yet to be determined.More news: Michael Bloomberg to file for Alabama 2020 presidential primary
Gao said that he had no further information on the location or timing.