S. Korea, US discuss nuclear exercises amid tension with North: Yoon

South Korea and the United States are discussing possible joint exercises using US nuclear assets, South Korean President Yoon Suk-yeol said, as North Korean leader Kim Jong Un labelled the South its “undoubted enemy” in flaring cross-border tensions.

Yoon's comments, in a newspaper interview published on Monday, come after he called for “war preparation” with an “overwhelming” capability, following a year marked by the North's record number of missile tests, and the intrusion of North Korean drones into the South last week.

“The nuclear weapons belong to the United States, but planning, information sharing, exercises and training should be jointly conducted by South Korea and the United States,” Yoon said in the interview with the Chosun Ilbo newspaper.

The newspaper quoted Yoon as saying the joint planning and exercises would be aimed at a more effective implementation of the US “extended deterrence”, and that Washington was also “quite positive” about the idea.

The term “extended deterrence” means the ability of the US military, particularly its nuclear forces, to deter attacks on US allies.

“We have nothing to announce today,” a Pentagon spokesperson said when asked about Yoon's comments, adding that the alliance remains “rock-solid”.

Yoon's remarks were published a day after North Korean state media reported that its leader Kim called for developing new intercontinental ballistic missiles (ICBMs) and an “exponential increase” of the country's nuclear arsenal.

At a meeting of the ruling Workers' Party meeting last week, Kim said South Korea has now become the North's “undoubted enemy” and rolled out new military goals, hinting at another year of intensive weapons tests and tension.

Inter-Korean ties have long been testy but have been even more frayed since Yoon took office in May, promising a tougher stance on the North.

On Sunday, North Korea fired a short-range ballistic missile off its east coast, in a rare late-night, New Year's Day weapons test, following three ballistic missiles launched on Saturday.

The North's official KCNA news agency said the projectiles were fired from its super-large multiple rocket launcher system, which Kim said “has South Korea as a whole within the range of strike and is capable of carrying tactical nuclear warheads.”

The North's race to advance its nuclear and missile programmes has renewed debate over South Korea's own nuclear armaments, but Yoon said in the Chosun Ilbo interview that maintaining the Treaty on the Non-Proliferation of Nuclear Weapons remained important.

To better cope with the North's growing threats, South Korea's military said on Monday it had established a new directorate under the Joint Chiefs of Staff to counter the North's nuclear and weapons of mass destruction capabilities.

Second in command of N. Korean military fired

North Korea has sacked Pak Jong Chon, the second most powerful military official after leader Kim Jong Un, state media reported.

Pak, vice chairman of the Central Military Commission of the ruling Workers' Party and a secretary of the party's Central Committee, was replaced by Ri Yong Gil at the committee's annual meeting last week, the official KCNA news agency said on Sunday.

No reason for the change was given. Pyongyang regularly revamps its leadership and the year-end party gathering has often been used to announce personnel reshuffles and major policy decisions.

State television showed Pak sitting in the front row of the podium with his head down during the meeting while other members raised their hands to vote on personnel issues. His seat was later shown unoccupied.

He was also absent in photos released on Monday by the official KCNA news agency of Kim's New Year's Day visit to the Kumsusan Palace of the Sun which houses the bodies of his grandfather and father, unlike in October when Pak accompanied Kim on a trip to the palace to mark a party anniversary.

The party's Central Military Commission, which is headed by Kim, is considered the country' most powerful military decision-making body, above the defence ministry.