"The increased moves of the USA and its vassal forces to impose sanctions and pressure ... will only increase our pace towards the ultimate completion of the state nuclear force", the North's foreign ministry spokesman said in a statement carried by its official KCNA news agency. The White House stated he also has a meeting scheduled with the South Korean president, which will focus on how to maximize economic and diplomatic pressure on North Korea.
The quake was detected in an area around Kilju, in northeastern North Korea, just 3.7 miles northwest of where the North conducted its sixth and most powerful nuclear test on September 3, according to an official from Seoul's Korea Meteorological Administration.
Head of nuclear test monitoring agency CTBTO is analysing the "unusual seismic activity".
"Developments in the peninsula nuclear issue up to this point prove that, no matter whether it is military threats in words or in action, they can not promote and advance a resolution", the foreign ministry spokesman, Lu Kang, said. The latest test was followed by a second magnitude 4.1 quake that experts said could have been caused by landslides or a tunnel collapsing after the explosion.
Seoul is within artillery range of North Korea, which beyond nuclear and conventional weapons is also believed to have a sizable chemical and biological arsenal. "The Punggye-ri nuclear test site remains ready for a (new) test", the ministry said. "None of us want war", she said on CNN.
"The depth is poorly constrained and has been held to 5 km by the seismologist", USGS said. The test came in the wake of tougher sanctions imposed by the United Nations following the country's sixth nuclear test early this month.
GETTYU.S. Defense Secretary Jim Mattis hinted about the existence of military options on North Korea
In a speech to the UN General Assembly on Tuesday, President Donald Trump warned North Korean leader Kim Jong-un that the United States, if threatened, would "totally destroy" his country of 26 million people.
Tens of thousands of North Koreans gathered in Pyongyang Saturday to applaud the regime's stance, their fists clenched as speakers repeated Kim's denigration of Trump as a "dotard".
Even as tensions rise, the United States and its allies have stuck to a hands-off policy when North Korea test-fires its missiles.
Russian Federation and China have both appealed for an end to the escalating rhetoric between Washington and Pyongyang.
A pair of Air Force bombers and four stealth fighter jets conducted the live-fire training mission over the Korean Peninsula, the US military's Pacific Command reported.
Monitoring groups estimate that the nuclear test conducted in North Korea earlier this month had a yield of 250 kilotons, which is 16 times the size of the U.S. bomb that destroyed Hiroshima in 1945.