US President Donald Trump on Thursday urged all countries to stop arming, financing and trading with the "murderous" North Korean regime even as he claimed that China had a solution to the Korean nuclear crisis.

Addressing a joint press conference with President Xi Jinping at the Great Hall of the People, Trump, on a three-day visit that began on Wednesday, said he and Xi had agreed not to replicate failed approaches to resolve the growing crisis.

North Korea figured majorly on the agenda when Xi and Trump held talks at the Great Hall of the People. Trump indicated that he wanted China to pressure North Korea to give up its nuclear designs.

While Xi promised cooperation and coordination, Trump said China had the solution to the problem.

"Our meeting ... was excellent, discussing North Korea and I do believe there is a solution to that, as you do," Trump told Xi. "We have the capacity to solve world problems for many years to come."

Xi said: "China is ready to work with the US to enhance cooperation and properly manage the differences in a spirit of mutual benefit."

He said the US and China had "more coordination and cooperation in North Korea nuclear issue and other world challenges. Right now China and US relations are at a new starting point".

At the press conference, Trump said all responsible countries must join together to stop arming and financing and even trading with the "murderous North Korean regime".

"Today, we discussed our mutual commitment to the complete denuclearisation of North Korea.

"We agreed on the need to fully implement all the Security Council resolutions on North Korea and to increase economic pressure until North Korea abandons its reckless and dangerous path."

China is the North's ally and its biggest trading partner. Washington believes that Beijing has influence over Pyongyang because of the close ties. Mao Zedong's son died fighting in Korea against the US in the 1950s.

China says it will do whatever possible to rein in North within the regulated framework of the UN but is not in favour of unilateral sanctions against the reclusive country.

"As long as we stand together with others, if necessary against those who threaten our civilization, that threat will never happen. It doesn't even have a chance," Trump said.

"The entire civilised world must unite to confront the North Korean menace and the entire world is watching us right now.

"Together we have enough power to finally liberate this region and the world from this serious nuclear menace. But it will require a collective effort, collective strength and collective devotion to winning the peace," Trump added.

Tensions between Washington and Pyongyang have escalated after North Korea's test firing of missiles and conducting its most powerful hydrogen test in September.

North Korea fears the US wants it to be merged with South Korea.

Trump also talked about the yawning trade deficit between two countries. He lavished praise on Xi, touting "great chemistry" between them. The US President blamed his predecessors, not China, for the problem.

"(The) US really has to change its policies because they've gotten so far behind on trade with China and frankly with many other countries. But it's too bad that past administrations allowed it to go so far."

He said: "I don't blame China. Who can blame a country that is able to take advantage of another country for the benefit of its citizens? I give China great credit."

The two countries announced memorandums of understanding to increase trade by $253 billion, which the leaders said was a sign of greater cooperation. The deals include purchases of Boeing aircraft, Ford automobiles, US soybeans and joint development of liquified natural gas in Alaska.

Trump is in China on the third leg of his five-nation Asia tour after stops in Japan and South Korea. He will later go to Vietnam and the Philippines.

This is Trump's first visit to China as US President and the third meeting with Xi this year.