"North Korea's nuclear weapons and missile development is a grave threat to peace and security in our world and it is unacceptable that others financially support this criminal, rogue regime", Mr Trump said as he joined Japanese PM Shinzo Abe and South Korean President Moon Jae-in for lunch.
A small natural disaster near North Korea's nuclear test site was probably not man-made, the nuclear proliferation watchdog and a South Korean official said, easing fears Pyongyang had exploded another nuclear bomb just weeks after its last one.
The situation on the Korean peninsula is getting more serious by the day and can not be allowed to spin out of control, Chinese Foreign Minister Wang Yi told his German counterpart, the state-run China News Service said this morning.
Experts say North Korea also uses shell companies to skirt rules. He said in remarks broadcast on South Korean TV that the countermeasures flagged by Kim might refer to a "strongest-ever" ground-level test of a hydrogen bomb in the Pacific.
As North Korea develops nuclear weapons and ballistic missiles that can reach the islands, Hawaii state lawmakers have been urging emergency management officials to update Cold War-era plans for coping with a nuclear attack.
The agency said it is analyzing the nature of the quake. The USGS measured this month's nuclear test at magnitude 6.3.
The majority of North Korea's oil likely comes from China, but the exact tally of oil exports remains unknown, as Beijing has not published such data since 2014.
South Korea's Meteorological Administration (KMA) confirmed has, however, confirmed an event of 3.0 magnitude and said it occurred in the Kilju area of North Hamgyeong Province.
"Two #Seismic Events! 0829UTC & much smaller @ 0443UTC unlikely Man-made!"
Mr Trump also said China was imposing major banking sanctions, but there was no immediate confirmation from the North's most important trading partner. At the United Nations, Trump called Kim "rocket man" and threatened to "totally destroy" North Korea.
Earlier, Russian Foreign Minister Sergei Lavrov compared US President Donald Trump and North Korean leader Kim Jong-un to children fighting in a kindergarten.