The North's last test, on September 3, was the country's most powerful detonation, triggering a much stronger 6.3-magnitude quake that was felt across the border in China.
North Korea said on Saturday that firing its rockets at the US mainland was "inevitable" after US President Donald Trump called Pyongyang's leader "rocket man", in a further escalation of rhetoric between the two leaders.
Earlier on Saturday, China said it will limit exports of refined petroleum products from October 1 and ban exports of condensates and liquefied natural gas immediately to comply with the latest United Nations sanctions. We can not conclusively confirm at this time the nature (natural or human-made) of the event.
The North has threatened to test a hydrogen bomb over the Pacific.
The Pentagon issued a statement after the mission was completed and confirmed that it was designated to show the many military options U.S President Donald Trump had to deal with the grave threat presented by the North Korean nuclear program.
Ri Yong-ho described Mr Trump as a "mentally deranged person full of megalomania" on a "suicide mission".
"This is the farthest north of the Demilitarized Zone (DMZ) any US fighter or bomber aircraft have flown off North Korea's coast in the 21st century", White said.
Chinese leaders were long the North's diplomatic protectors but express increasing frustration with the government of Kim Jong Un.
All of North Korea's six nuclear tests registered as earthquakes of magnitude 4.3 or above.
"This event occurred in the area of the previous North Korean Nuclear tests". "I will surely and definitely tame the mentally deranged United States dotard with fire".
Trump blasted Pyongyang in his U.N. General Assembly speech last week, and began referring to Kim as "Rocket Man" on Twitter and at a rally Friday.
"Trump, the president of so-called "power, ' is mad enough to wag his tongue without any consideration that he would 'totally destroy" a sovereign state".
The mission in worldwide airspace on Saturday was said to show how seriously President Donald Trump takes North Korea's "reckless behavior".
China also will ban textile imports from the North, the ministry said.
"It is a foolish misjudgment if Trump's gang thinks that America is safe because it's far away from the Korean Peninsula".
China announced Saturday that it will limit oil exports to North Korea under United Nations sanctions over its nuclear and missile development, further reducing support from Pyongyang's last major trading partner, energy supplier and diplomatic ally.
China's Ministry of Commerce said Saturday it would limit refined petroleum exports starting October 1 and ban the import of North Korean textiles immediately.
And it's possible that North Korea is able to undermine them. On Thursday, the USA unveiled its own set of economic sanctions targeting North Korea.