China must take more measures to “choke off” North Korea’s resources and force it to abandon its nuclear weapons programme, US National Security Adviser Lt Gen HR McMaster said on Sunday, conceding that the new sanctions imposed on Pyongyang may not be enough.

China is North Korea’s largest trading partner and the US has urged Beijing to use diplomatic and economic pressure – such as limiting its role as the main exporter of oil – to dissuade Kim Jong Un’s regime from pursuing nuclear weapons.

“They (Chinese) have to take some steps, though, that restrict trade in any way that we can with this regime, to choke off the resources that allowed this regime to continue to prioritise their military efforts, their missile efforts, their nuclear efforts over the well-being of their own people,” Lt Gen McMaster told Fox News.

North Korea launched an inter-continental ballistic missile in July, another of medium range in August, and this month tested what is increasingly believed to be a hydrogen bomb. It has launched two missiles over the Japanese territory in less a month.

McMaster said it really depends on how China sees the threat from North Korea continue to manifest itself and in their judgement about how much time they have.

He said the US was “out of road” because negotiations held in the past with the North delivered “an unsatisfactory agreement, an agreement that the North Korean regime breaks.”

The top US official said America has to move “with a great deal of urgency” on sanctions, on diplomacy and even military front if required to deter the Kim Jong-Un regime.

In another interview to ABC News, McMaster said sanctions imposed against North Korea were not going to be enough.

“We all have our doubts about whether or not that’s going to be enough. So we have to prepare all options. We have to make sure all options are under development to ensure that this regime cannot threaten the world with a nuclear weapon,” he said.

“So the critical thing is going to be to get all countries, everyone to do all they can to enforce those sanctions, to do everything they can, short of a military conflict, to resolve this problem,” he said.

About a tweet US President Donald Trump sent out this morning apparently mocking Kim as “Rocket Man”, McMaster said the tweet reminded him of a cover of ‘The Economist’ magazine a few years ago.

“But, of course, that’s where the rockets are coming from. Rockets, though, we ought to probably not laugh too much about because they do represent a great threat to everyone,” he said.

Meanwhile, Secretary of State Rex Tillerson said the US strategy against North Korea involves a “peaceful pressure campaign” on Pyongyang.

“All of that (international pressure is) designed to bring North Korea to the table for constructive, productive dialogue. If our diplomatic efforts fail though, our military option will be the only one left,” he said.