The phase one trade agreement between China and the United States, signed Wednesday in Washington, showed that the world's top two economies can work out their issues effectively on the basis of equality and mutual respect, Chinese President Xi Jinping said in a message delivered at the deal-signing ceremony.

In the next step, the two sides need to implement the agreement "in real earnest" and optimize its positive impact for even greater progress in China-US trade and economic cooperation, Xi said in the message delivered to US President Donald Trump by Vice-Premier Liu He.

Maintaining the healthy and steady growth of China-US relations serves the interest of both countries and requires joint efforts from both sides, Xi said in the message.

"In that spirit, I hope the US side will treat fairly Chinese companies and their regular trade and investment activities, and give support to the collaboration between enterprises, research institutes, and schools and colleges of the two countries as it will help enhance mutual trust and cooperation between us," Xi said.

"I believe that under our guidance, China-US relations will deliver more results and bring greater benefits to our peoples in the year ahead," the Chinese president said.

The trade deal, inked by Trump and Liu, China's top trade negotiator, capped nearly two years of a bruising trade battle that had roiled stock markets, ruined businesses and weighed on global growth.

Trump said the signing represents a "momentous step" toward a future of fair and reciprocal trade.

"This is an unbelievable deal for the United States. And, ultimately, it's a great deal for both countries. And it's going to also lead to even a more stable peace throughout the world," he said.