North Korea: US, China agree 'provocative' nuclear program cannot continue, Trump adviser says

The United States and China both agree that North Korea's nuclear program cannot be allowed to continue, according to US national security adviser HR McMaster.

General McMaster's comments came as US Vice-President Mike Pence touched down in South Korea where he addressed Seoul-based US troops, saying US commitment to South Korea was unwavering.

"Let me assure you under President Trump's leadership, our resolve has never been stronger," he said.

"Our commitment to this historic alliance with the courageous people of South Korea has never been stronger."

Mr Pence was beginning a 10-day trip to Asia, including Australia, in what his aides said was a sign of US commitment to its allies in the face of rising tension.

After days of sabre-rattling, the North fired an unidentified land-based missile on Sunday that "blew up almost immediately", the US Pacific Command said.

While the failed test was initially met with a muted response from Washington, US President Donald Trump's national security adviser later signalled the US took the action seriously.

"This latest missile test just fits into a pattern of provocative and destabilising and threatening behaviour on the part of the North Korean regime," General McMaster told the This Week program.

"There is an international consensus now, including the Chinese leadership, that this is a situation that just cannot continue.

"The President has asked the National Security Council to integrate the efforts of the Department of Defence, State, our intelligence agencies — so we can provide options and have them ready for him if this pattern of destabilising behaviour continues and if the North Korean regime refuses to denuclearise."

South Korea said it would respond strongly to any further provocation.

"North Korea showing a variety of offensive missiles at [Saturday's] military parade and daring to fire a ballistic missile [on Sunday] is a show of force that threatens the whole world," South Korea's Foreign Ministry said in a statement.

Mr Trump on Sunday acknowledged China's help with the North Korean issue, linking it to a softer line taken on North Korean ally China's management of its currency.

After months of labelling China "currency manipulator", Mr Trump's softer rhetoric towards Beijing comes as the US tries to foster warmer relations in an effort to ease tension on the Korean peninsula.

In response to Pyongyang's missile test China's top diplomat Yang Jiechi spoke with US Secretary of State, Rex Tillerson, to exchange views on the "situation on the Korean peninsula", China's official Xinhua News Agency said.

Mr Yang said the two sides should maintain dialogue.