China's ambassador to the US Cui Tiankai

A Chinese envoy to the US on Wednesday expressed harsh criticism of what he calls "extreme rhetoric," including terms such as "decoupling" and a "new Cold War" between China and the US, and stressed that China will not back down on matters related to its core national interests.

The comments from Cui Tiankai, the Chinese ambassador to Washington, came as officials from China and the US are set to sign a widely expected phase one trade agreement, underscoring the fact that tensions between the world's two biggest economies could linger despite the interim deal.

"Our ties are now faced with a difficult situation rarely seen in the past 40 years. Some forces are going all out to demonize China and provoke a confrontation between us," Cui said at the Lunar New Year Gala of the China General Chamber of Commerce in New York City. He added, "What they are doing has seriously damaged our relations and put world peace and prosperity in real peril."

China and the US reached a consensus on the text of the phase one deal in December. And on Thursday the Chinese Ministry of Commerce announced that Chinese Vice-Premier Liu He, who is China's top trade negotiator with the US, will visit Washington from January 13-15 to sign the agreement with the US.

Although the two countries are close to signing the deal, the ambassador's comments indicate there are still challenges and hurdles ahead, Han Bing, an expert at the Institute of World Economics and Politics under the Chinese Academy of Social Sciences, told the Global Times on Thursday.

"The US has determined its strategy to contain China in 2018, and it has received the united support of the country's two parties. What [the US] has done to China since then has manifested from this strategy. So even if the two sides sign the phase one deal, it won't solve their fundamental problems in a short period of time, and the situation could even become worse," Han said.

However, despite his criticisms, the ambassador also expressed optimism for the future of the bilateral ties, as "the real strength of this important relationship lies in both countries' abilities to overcome challenges and difficulties."

"No one can stop the friendly exchanges between the 1.7 billion Chinese and American people, and no one has the power to lead our two great nations toward conflict and confrontation. I believe that as long as we pull together, the great ship of China-US relations will break the waves, navigate out of choppy waters and sail on toward better shores," Cui said.