China's seismic service CENC on Saturday detected a zero-depth, 3.4-magnitude quake in North Korea, calling it a "suspected explosion".
An atmospheric thermonuclear blast would also raise the risks of damage caused by an electromagnetic pulse, an intense wave of electrical energy generated by the explosion that could destroy electronic devices and equipment over a vast area, Lee said.
Seismic activity was detected Saturday near the site of North Korea's Punggye-ri nuclear site, but it is not known whether a nuclear test caused the development.
The natural disaster is reported to have occurred near a nuclear test site and previous quakes have occurred during weapons' tests.
Washington announced tougher restrictions Friday aimed at curbing North Korea's nuclear and ballistic missile program, building on new tough United Nations sanctions aimed to choke Pyongyang of cash.
A second, much smaller natural disaster was detected earlier, according to the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO), a group tasked with monitoring weapons tests.
South Korea's Yonhap news agency quoted a weather agency official who said that "a sound wave, which is usually generated in the event of an artificial quake, was not detected". The US Geological Survey said the quake was at a depth of three miles.
Remains to be seen whether this new natural disaster has also been caused by yet another firing of nuclear missile.
There was no immediate reaction from China's Foreign Ministry, but the news was widely reported by Chinese state media outlets and on social media.
China's central bank has told banks to strictly implement United Nations sanctions against North Korea, four sources told Reuters, amid US concerns that Beijing has not been tough enough over Pyongyang's repeated nuclear tests.
He says the US keeps pressing Russian Federation and China to do more to squeeze Pyongyang economically.
North Korea in past months has been stepping up the aggressiveness of its nuclear and missile tests. The last test on 3 September registered as a 6.3 magnitude quake.
Korean leader Kim Jong Un branded the speech the "most ferocious declaration of war in history" and said he would consider the "highest level of hardline countermeasure" in response.
The North conducted its sixth and most powerful nuclear test in September.
North Korean Foreign Minister Ri Yong Ho wouldn't have spoken without approval from Pyongyang's top leadership when he suggested to reporters in NY on Friday that the country could conduct an atmospheric hydrogen bomb test to fulfill the vows of the country's leader Kim Jong Un.
Trump has dubbed Kim a "madman" and sought to ratchet up sanctions against the isolated regime, which says it needs nuclear weapons to protect itself against the threat of invasion.
A day earlier, Kim reacted to Trump's provocative speech at the U.N.by equating the US president to "a frightened dog" and a "mentally deranged USA dotard", employing an obscure insult for someone declining into senility.