The Pentagon has described North Korea's recently launched intercontinental ballistic missile (ICBM) as a new type of missile that "we've not seen before," and condemned the launch as escalatory and destabilising.
Pentagon spokesman Navy Captain Jeff Davis told a news briefing that the ICBM was fired from a mobile launcher and confirmed the presence of a re-entry vehicle on top of it.
Meanwhile, US President Donald Trump has denounced China's trade with North Korea and cast doubt on whether Beijing is working with Washington to counter the North Korean nuclear threat.
"Trade between China and North Korea grew almost 40 pct in the first quarter. So much for China working with us - but we had to give it a try!" Mr Trump said in a Twitter post on Wednesday shortly before taking off for a G20 summit in Germany.
In an earlier tweet, Mr Trump said: "The United States made some of the worst Trade Deals in world history. Why should we continue these deals with countries that do not help us?"
During the G20 summit, Mr Trump will meet for the second time with Chinese President Xi Jinping, with whom he has expressed frustration for failing to use enough leverage to curb North Korea's nuclear program.
China is North Korea's largest trading partner and ally.
Data released in April by Beijing showed China's trade with North Korea grew 37.4 percent in the first quarter this year from the same period in 2016, according to reports in the New York Times and Financial Times. Chinese exports surged 54.5 percent and imports increased 18.4 percent, according to the General Administration of Customs.