The United States and South Korea are preparing "a coordinated and concrete response to a series of scenarios, including the use of nuclear weapons by North Korea,"a spokesman for the White House's National Security Council said today.

The spokesman added that South Korean President Yun Suk-Yul and US President Joe Biden "tasked their teams with planning an effective coordinated response to a number of scenarios, including the use of nuclear weapons by North Korea".

But the spokesman clarified that these preparations will not include "joint nuclear exercises", since South Korea does not have nuclear weapons.

At the beginning of 2023, North Korean leader Kim Jong-Un called for a "massive" increase in the North Korean nuclear arsenal, including the mass production of tactical nuclear weapons and the development of new missiles for use in nuclear counter-strikes, according to state media.

The North's official KCNA news agency reported that Kim said after a key meeting of the ruling Workers ' Party in Pyongyang that the country should "massively strengthen military power" in 2023 in response to what he called us and South Korean hostility.