The US and China pledged yesterday to work together in addressing the threat posed by North Korea's nuclear programme, as US Secretary of State Rex Tillerson warned the situation had reached a "dangerous level."

The language from Tillerson and his Chinese counterpart after talks in Beijing was notably conciliatory after a run-up in which US President Donald Trump accused China of doing nothing to control its rogue neighbour while Beijing blamed Washington for fuelling hostilities.

"I think we share a common view and a sense that tensions in the peninsula are quite high right now and that things have reached a rather dangerous level," Tillerson said after talks with Chinese Foreign Minister Wang Yi.

"We will work together to see if we cannot bring the government in Pyongyang to a place where they want to make a different course, make a course correction, and move away from the development of nuclear weapons."

Tillerson arrived in Beijing earlier yesterday after visits to US allies Japan and South Korea where he said the US would no longer observe the "failed" approach of patient diplomacy favoured by Beijing and followed by the Obama administration.

Trump upped the pressure in a Friday Twitter blast accusing Beijing of failing to use its leverage as North Korea's key diplomatic and trade partner.

"North Korea is behaving very badly. They have been 'playing' the United States for years. China has done little to help!" Trump said.

The tougher US talk followed two North Korean nuclear tests last year and recent missile launches, including a salvo earlier this month that Pyongyang described as practice for an attack on US bases in Japan.

Beijing shares US concerns over Pyongyang's nuclearisation but is careful not to provoke North Korea.

Beijing is deeply reluctant to put harsh pressure on the unpredictable North lest it trigger a confrontation or a messy regime collapse.

China has hit back at the US, angrily accusing it of escalating the situation by holding military exercises with its ally Seoul and deploying an anti-missile system in South Korea.

But it took one of its toughest steps yet in February, halting all imports of North Korean coal -- a key source of income for the impoverished state -- for the rest of this year.

Wang Dong, a North Korea expert at Peking University, said it was wrong to think Beijing can control the unpredictable and head-strong Pyongyang.

"It is unreasonable for the United States to accuse China of doing nothing on the DPRK (North Korea)," Wang said.

"This is an extremely complex and sensitive issue. There is no one magic formula."