Officials from the United States, South Korea and Japan met in Seoul on Friday for talks on North Korea amid signs the isolated country is preparing to conduct a nuclear test for the first time since 2017.
US Special Representative Sung Kim met his South Korean and Japanese counterparts, Kim Gunn and Funakoshi Takehiro, after a US assessment that the North was preparing its Punggye-ri test site for what would be its seventh nuclear test.
"We are preparing for all contingencies in close coordination with our Japanese and ROK allies," Kim said at the beginning of the meeting, referring to South Korea by the initials of its official name, the Republic of Korea.
This year, North Korea has tested several ballistic missiles, including one thought to be its largest intercontinental ballistic missile, in violation of UN sanctions.
"We want to make clear to the DPRK that its unlawful and destabilising activities have consequences and that the international community will not accept these actions as normal," the US envoy said, referring to North Korea.
South Korea's newly appointed nuclear envoy, Kim Gunn, said North Korea's "relentless pursuit of nuclear weapons will only end up strengthening our deterrence".
"The course that Pyongyang is currently embarking on has only one inevitable destination: reduce security for North Korea itself," the South Korean diplomat said.
Last week, the United States called for more UN sanctions on North Korea over its ballistic missile launches, but China and Russia vetoed the suggestion, publicly splitting the UN Security Council on North Korea for the first time since it started punishing it in 2006, when it conducted its first nuclear test.
Japan's Funakoshi stressed the need for coordination, vowing to "enhance regional deterrence, including trilateral security cooperation".
The officials said the door for dialogue was open and expressed concern over the Covid-19 situation in North Korea.
Earlier, US Deputy Secretary of State Wendy Sherman said the United States would not link humanitarian aid for North Korea as it battles Covid to denuclearisation.