Beijing/Hong Kong (CNN Business)The United States and China say they're optimistic about the state of their trade agreement — even as the two superpowers fight over a slew of other issues, including technology and national security.

High-level authorities from both countries — including US Treasury Secretary Steven Mnuchin, US Trade Representative Robert Lighthizer and Chinese Vice Premier Liu He — spoke by telephone Monday evening US time, according to statements released by their respective governments.

"Both sides see progress and are committed to taking the steps necessary to ensure the success of the agreement," Lighthizer's office said in a statement, referring to a "phase one" trade deal reached earlier this year.

China's Ministry of Commerce called the talks "a constructive dialogue" in its own statement, adding that the countries agreed "to create conditions and atmosphere to continue pushing forward" the deal.