The US and China have agreed to go ahead with a further set of trade negotiations at the end of January, The Wall Street Journal reports.

The progress follows a productive set of negotiations in Beijing this week.

The talks, however, could be delayed by the ongoing shutdown of the US government, officials with knowledge of the discussions warned.

On Saturday, the shutdown will become the longest in US history.

The US and China have agreed to go ahead with a further set of trade negotiations at the end of January, with more senior officials from both sides set to participate in the talks, to be held in Washington, DC, The Wall Street Journal reported Friday.

A Chinese delegation sent from Beijing is expected to be led by Vice Premier Liu He, China's most senior trade official who is also one of President Xi Jinping's closest allies. The US delegation is expected to be headed by Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin.

According to The Journal, the talks are set to take place January 30-31 but could be derailed by the partial shutdown of the US government over funding for President Donald Trump's proposed wall on the southern US border.

The shutdown is now over 20 days old, and if a compromise is not reached Friday, it will on Saturday become the longest in US history.

Read more: The government shutdown threatens the US with a credit-rating cut for only the 2nd time in history

News of fresh talks comes just two days after the end of talks between more junior officials from the two sides in Beijing earlier in the week. A US delegation led by Jeffrey Gerrish, the deputy trade representative, visited the Chinese capital at the start of this week, holding talks that were productive but did not yield any major breakthroughs.

A US statement released after the talks finished said the delegates discussed "ways to achieve fairness, reciprocity, and balance in trade" between the two nations and agreed that any trade deal needed to provide "complete implementation subject to ongoing verification and effective enforcement."

This week's talks, and the talks scheduled for the end of January, are part of a dialogue between the US and China after a tentative agreement was made at November's G20 summit in Buenos Aires, Argentina.

That agreement saw China commit to renewed purchases of US agricultural goods like soybeans, in return for the delay of a fresh swath of tariffs Washington was set to impose on Chinese goods.

Numerous sticking points remain, however, including Washington's desire for better protection of American intellectual property in China and the further opening of Chinese markets to foreign companies.