There is still much to be done for China and the United States to strike a trade deal, said a spokesman at China’s commerce ministry Thursday as U.S. officials landed in Beijing for a new round of talks.

U.S. trade officials led by Treasury Secretary Steven Mnuchin and Trade Representative Robert Lighthizer arrived in Beijing Thursday afternoon for the eighth round of trade talks between the two countries, Ministry of Commerce Spokesman Gao Feng said at a press conference.

The two countries are reported to be close to an accord that would end their nine-month trade dispute. But Gao said there are still outstanding issues to be discussed.

“The two sides have made some progress recently, but there’s still a lot of work to be done,” Gao said.

One of the sticking points is disagreement on enforcement. The U.S. is pushing China to accept a mechanism to allow Washington to regularly review Beijing’s compliance with terms of the agreement and put tariffs back in place should it fail the verification.

The two sides will hold a working dinner Thursday evening with a full day of talks planned for Friday, Gao said. Next week, Chinese Vice Premier Liu He is scheduled to travel to Washington for another round of talks.

Related: Beijing Wants Enforcement Mechanism in U.S. Trade Deal to Work Both Ways