The United States and its allies will take appropriate steps to hold North Korea accountable should the recalcitrant country conduct a nuclear test, a National Security Council (NSC) spokesperson said Tuesday.

John Kirby, NSC coordinator for strategic communications, also noted the North may continue to be ready to conduct a test.

"We have been very clear that North Korea could be ready to conduct a nuclear test. That is something we said very, very openly," Kirby said in a press briefing, held virtually.

"These tests have in the past and if they test in the future will in the future just add to the insecurity and instability on the Korean Peninsula," he added. "Again, we would react appropriately along with allies and partners."

Seoul and Washington have both said the North appears to have completed all preparations for what will be its seventh nuclear test, with US officials earlier anticipating Pyongyang to conduct a test as early as in May.

Earlier reports have suggested Pyongyang may have been forced to postpone its test due to its ongoing COVID-19 pandemic and economic difficulties.

North Korea began reporting its COVID-19 cases in May. It claims its daily new infection cases have since dwindled to below 50 as of this week.

South Korea's Unification Minister Kwon Young-se on Monday hinted at the possibility of North Korea conducting a nuclear test this week to mark the end of the 1950-53 Korean War 69 years ago, which it calls "Victory Day."

State department spokesperson Ned Price said US concerns over a potential North Korea nuclear test "have not abated" when asked if Washington shared Seoul's assessment.

"You have heard assessments that our ROK counterparts have made public that the DPRK regime has conducted all necessary preparations for a potential nuclear test. That has not changed," he said in a department press briefing, referring to South and North Korea by their official names, respectively the Republic of Korea and the People's Democratic Republic of Korea.

"We have continued to be very clear in our public statements but also working closely with our allies and partners in the Indo-Pacific and well beyond to make clear that any additional nuclear tests that the DPRK conducts would carry tremendous costs," added Price.

Kirby said the US will continue to closely monitor the reclusive state for any signs of a nuclear test.

"I won't speculate about the timing here, or what that can look like," he said.

"We are obviously going to watch this very, very closely for any possibility of a nuclear test," added Kirby. (Yonhap)