"We should never underestimate it", Choi said.
South Korean media say the nation's new president will visit the White House late next month amid worries over North Korea's escalating progress in its nuclear and missile arsenal.
Ambassadors from France and the U.K. have said they favor tougher sanctions against Pyongyang but a consensus hasn't been reached in the 15-member Security Council, where Russian Federation, the U.S., U.K., China and France have veto power.
"We are willing to talk, but not until we see a total stop of the nuclear process and of any tests there", Haley said.
Last month, U.S. Secretary of State Rex Tillerson directly called on the worldwide community to act before North Korea carries out a more serious provocation and to impose new sanctions. "We also agreed that dialogue with North Korea could happen under the 'right conditions'".
"I believe that this was spread for the objective of causing as much damage as possible", said Matthew Hickey, a co-founder of British cyber consulting firm Hacker House. "We can not be in a "wait and see" mode until the next provocation occurs".
Analysts said the test flight, if conducted on a normal rather than a high trajectory, would have travelled at least 4,000km. In 2014, the United States charged North Korea with attacking computers at Sony in retaliation for the creation of a comedy titled "The Interview" that was about a C.I.A. plot to kill North Korean leader Kim Jong-Un.
China has strongly opposed THAAD, saying it can spy into its territory, and South Korean companies have been hit in China by a nationalist backlash over the deployment. It is worth noting that other cybersecurity experts in Russia, United States and Israel have noticed some links which may have to do with North Korea.
"If you are a country that is supplying or supporting North Korea, we will call you out on it", Haley said.
The U.N. Security Council first imposed sanctions on North Korea in 2006 and has strengthened the measures in response to its five nuclear tests and two long-range rocket launches. "Microsoft said it directly: the initial source of this virus is the United States security agencies", he said in Beijing on Monday.
"We have underestimated North Korea so far that since North Korea is poor, it wouldn't have any technologies".
There, he suggested that the successful missile, which the North Koreans call the Hwasong-12, appeared to be a smaller version of the KN-08, a code name for Korea North Type 8.
Washington has warned North Korea that the "era of strategic patience" they enjoyed under former President Barack Obama would not continue under current President Donald Trump. "Clearly, there is a lot more leverage that China has, and we would like China to use", he said. Pyongyang is threatening a sixth nuclear test.
Speaking of the enforcement of worldwide sanctions, she added this warning: "The United States is not past looking at third-country entities who are helping North Korea, and putting sanctions on them, because if you are supporting North Korea, you are against the rest of the global community".
More than 300,000 computers in 150 countries have been infected with the WannaCry "ransomware" virus since the attack, crippling organisations from government agencies and global companies.