US President Donald Trump and his Chinese counterpart Xi Jinping have announced making progress in narrowing their differences during their Florida summit, but did not elaborate on the achievements.

As the two leaders wrapped up their meeting on Friday at Trump's Mar-a-Lago resort, the US leader said: "We have made tremendous progress in our relationship with China".

"We will be making additional progress. The relationship developed by President Xi and myself I think is outstanding," Trump said in contrast to the anti-China rhetoric of his 2016 election campaign.

"And I believe lots of very potentially bad problems will be going away," he added, without offering any indication of what differences had been narrowed between the world's two biggest economies.

Xi also spoke in mostly positive terms, but offered only broad generalities.

"We have engaged in deeper understanding, and have built a trust - a preliminary working relationship and friendship," he said.

"I believe we will keep developing in a stable way to form friendly relations ... For the peace and stability of the world, we will also fulfill our historical responsibility."

"Well, I agree with you 100 percent, Mr President," Trump replied, speaking to a small pool of journalists allowed into the room for a few minutes.

The two men had a working lunch before Xi's motorcade left the resort, ending the summit.

'Theft of jobs'

Trump had said he intended to raise concerns about China's trade practices and press Xi to do more to rein in North Korea's missile and nuclear programmes.

During his campaign, Trump promised to stop what he called the theft of American jobs by China and to rebuild the country's manufacturing base.

Many blue-collar workers helped propel him to his unexpected election victory on November 8 and Trump is under pressure to deliver for them.

The Republican president, who took office on January 20, tweeted last week that the US could no longer tolerate massive trade deficits and job losses and that his meeting with Xi "will be a very difficult one".

On Friday, Trump and Xi, politicians with distinctly different styles and experience levels, appeared cordial and businesslike in their interactions, with no outward sign of tensions.