The US and China moved closer to a trade agreement on a Friday evening phone call between the two countries’ top negotiators, according to statements from both sides.

Chinese Vice-Premier Liu He, speaking with US Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin “reached consensus on principles” concerning their 17 month-old trade war, China’s commerce ministry said, without specifying which ones.

“The two sides conducted serious and constructive discussions on properly addressing their core concerns,” the ministry added in its brief statement.

Meanwhile, USTR said in a statement that the two sides “made progress in a variety of areas and are in the process of resolving outstanding issues”, also without elaborating on which areas or issues were discussed.

“Discussions will continue at the deputy level,” USTR added.

Minister of Commerce Zhong Shan, Governor of the People’s Bank of China Yi Gang, and Deputy Director of the National Development and Reform Commission Ning Jizhen also were on the call, the Chinese ministry said, adding that “the two sides discussed the next consultations”.

Chinese President Xi Jinping and US President Donald Trump were expected to meet after the Asia-Pacific Economic Cooperation summit in Santiago, Chile to sign a “phase-one” trade deal touted last month, which would lead to greater purchases by China of US agricultural goods and provide greater intellectual property protections.

That interim deal largely avoided the more fundamental structural issues that would be left to a phase-two, and possibly a phase-three agreement.

Trade envoys from Beijing and Washington had been working ever since to set the text of the interim trade agreement the two leaders would sign.

The US government wants China to end heavy state subsidies and to agree to an enforcement mechanism to curb China’s practice of forcing foreign companies to transfer proprietary technology to Chinese joint venture partners, among other measures.

However, China has balked on making structural changes that would address these demands. Disagreements over how an enforcement mechanism would work was one factor in the breakdown of talks earlier this year.

Sean King, a former US trade official who is now senior vice-president of political strategy firm Park Strategies, said Beijing might want to get a phase-one deal done as soon as possible to avert another round of tariffs set to take effect next month.

China’s government “is likely also want to avoid any such early deal negotiations dragging on into the Democratic primary season, which might only further politicise matters,” he said.

“I think we’ll eventually reach some sort of deal with Beijing, but I’m not sure how much it will mean in practical terms … Its macroeconomic construct can’t fundamentally and/or structurally change as US companies would like it to,” King added.