The US on Thursday said that there are early indications that China is doing a better job than before on enforcing UN Security Council sanctions on North Korea.

But at the same time it noted that it was too early to arrive at any conclusion on this issue.

“You have seen some early indications of China doing a better job enforcing existing UN sanctions on North Korea. You can see in the Chinese press and in other areas that China is really making a clear effort to communicate to North Korea that its behaviour, its provocative behaviour, the nuclear tests, missile tests can't be tolerated,” a senior official with the Trump administration said.

“So I think you have seen two things an acknowledgement of the threat to China, but I think you have also seen a willingness for China to take this problem on in new ways. We ought to suspend judgment until we see how this develops in the coming days, months, so forth,” the official said in response to a question.

But he also noted that North Korea's behaviour also poses a threat to Chinese interests and security.

“What is different about how China is viewing the problem in North Korea today is that China is viewing that problem as a threat not only to US interests and security, or South Korea and/or Japanese interests and security, but also a threat to Chinese interests and security.And so I think that is a big shift in and of itself,” the official said.

China on February 18 imposed a halt on coal imports from North Korea until the end of 2017, hardening its stance after a new missile test by Pyongyang, in accordance with new sanctions adopted by the UN Security Council.

The State Department said China has taken some steps against North Korea, but it needs to take more such steps.

China's influence on North Korea is probably more than that of any other country and Beijing needs to exercise that influence on Pyongyang, said State Department Acting Spokesman Mark Toner.

The US, however, dismissed China's concerns on the US deployment of THAAD (Terminal High Altitude Area Defence) missile in South Korea.

“THAAD is a defensive system and it is being deployed, frankly, out of concern over South Korea's vulnerability to North Korea's continued aggressive behaviour. That's all it is,” Toner said.

The US and South Korea argue that the THAAD is aimed at countering missile threat from North Korea. But China says most of the THAAD systems can monitor best part of its territory.