Antony Blinken
Antony Blinken Reuters

The United States and South Korea warned on Monday of a “swift response” if North Korea conducts a nuclear test, including US military "adjustments," but again offered talks as a way out, AFP reported.

The two allies have warned that North Korea could at any time test its first nuclear weapon since 2017, after months of escalating tensions including missile tests and Pyongyang's rebuffing of overtures from President Joe Biden's administration.

Meeting his South Korean counterpart, US Secretary of State Antony Blinken said that the United States was working with allies in Tokyo and Seoul "to be able to respond quickly should the North Koreans proceed with such a test."

"And we are prepared to make both short- and longer-term adjustments to our military posture as appropriate," he added.

"Until the regime in Pyongyang changes course, we will continue to keep the pressure on."

At the same time, Blinken reiterated the United States has "no hostile intent" toward the North, formally known as the Democratic People's Republic of Korea.

"We'll continue to reach out to the DPRK. We're committed to pursuing a diplomatic approach," Blinken said.

Both Blinken and South Korean Foreign Minister Park Jin said their government was ready to negotiate with Pyongyang "without preconditions."

North Korea has conducted more than a dozen weapons tests since January, including the firing an intercontinental ballistic missile at full range for the first time since 2017.

Last month, it fired a volley of missiles, including possibly its largest intercontinental ballistic missile.

North Korea has ramped up its missile tests ever since talks with Washington on denuclearization failed.

Former US President Donald Trump tried to reach an agreement with North Korea while in office. Kim and Trump met in Hanoi in 2019 for a summit that left nuclear talks at a standstill.

The pair had met three times since June 2018 but made little progress towards denuclearization.

The Biden administration reached out to North Korea shortly after taking office, but the country did not respond to those overtures.

The Biden administration says it is ready to start talks with North Korea without preconditions, but would pursue working-level negotiations and not the pageantry of another summit.