US says 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 is too early to arrive at any conclusion on this issue, a senior official with the Trump administration said. But he also noted that North Korea's behaviour also poses a threat to Chinese interests and security.<br/><br/>China on February 18th 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. <br/><br/>State Department Acting Spokesman Mark Toner said that China's influence on North Korea is probably more than that of any other country and Beijing needs to exercise that influence on Pyongyang. <br/><br/>The US, however, dismissed China's concerns on the US deployment of THAAD missile in South Korea. 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.