The deadline for the United States and China to reach an agreement is looming ever closer, with further US tariffs set to come into effect on Dec 15. Although the US president could push back that deadline, as he did in October, there has been no indication yet that he will. And with a date and venue for their highly anticipated phase one deal having bitten the dust and no alternatives being forthcoming, there have been growing concerns that the feel-good consensus that some kind of deal was on the cards may prove vulnerable to the ravages of time.

It is therefore heartening to learn that the top trade negotiators of China and the US discussed matters relating to each other's core concerns in a telephone conversation on Tuesday morning.

According to a statement by China's Ministry of Commerce, the two agreed to maintain communication on the remaining issues of a first phase deal. They also agreed to continue to keep in touch to fix the "remaining issues" that are not yet resolved in their negotiations.

It is the fourth such conversation between Vice-Premier Liu He and US Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin since their last round of face-to-face discussions in Washington in October, indicating that the two sides are keen to maintain regular communication and share a high level of willingness to conclude their proposed phase one deal.

That deal is important for both sides and the world economy as a whole. The US-initiated trade frictions with China and other countries have ruffled the global financial market, dampened investors' confidence, affected global trade growth and reduced economic activities worldwide.

In the case of the US, although its purchasing managers' index rose to a seven-month high in November, its GDP growth is set to slow due to the impact of elevated tariffs as a result of its trade frictions with other countries, primarily China.

As with all kinds of negotiations, there is no doubt that details are still being ironed out before the deal is finalized, but with an agreement in place in spirit, it is presumably the nitty gritty of which side does what and when that is the subject of discussions.

Negotiators from both countries should demonstrate their utmost sincerity and patience and abide by the principle of mutual trust and mutual respect to ensure the deal still pending comes to fruition.