SEOUL >> North Korean leader Kim Jong Un supervised a live-fire artillery drill simulating an attack on a South Korean airfield and called for his troops to be ready to respond to the enemies’ “frantic war preparation moves” — apparently referring to the recent series of military drills between the United States and South Korea.

The North Korean state media report Friday came a day after South Korea’s military detected the North firing at least one short-range ballistic missile toward the sea from a site near the western coastal city of Nampo. The South’s Joint Chiefs of Staff was assessing whether more missiles may have been launched simultaneously.

The United States has recently sent long-range B-1B and B-52 bombers for several rounds of joint aerial drills with South Korean warplanes. The allies are also preparing this month for their biggest combined field training exercise in years to counter the growing threat of Kim’s growing nuclear arsenal. North Korea views regular U.S.-South Korean military exercises as invasion rehearsals.

Pyongyang’s official Korean Central News Agency said Kim urged his troops to be prepared to “overwhelmingly respond to and contain” the military action of the North’s enemies, which he said were proceeding with “all sorts of more frantic war preparation moves.”

He said frontline units should sharpen their capabilities to carry out their two main “strategic missions, that is, first to deter war and second to take the initiative in war.”

South Korea’s Unification Ministry later Friday urged North Korea to stop raising tensions with “reckless nuclear and missile programs and military provocations.” Vice spokesperson Lee Hyo-jung told reporters that North Korea must focus instead on caring for people’s livelihoods and take a path toward building peace on the Korean Peninsula.

The KCNA report did not specify what types of weapons were involved in Thursday’s exercise or how many rockets were fired. Some of the North’s newer short-range weapons targeting South Korea includes large-sized multiple rocket launchers that experts say blur the boundaries between artillery and ballistic missile systems.

North Korea describes some of its more advanced short-range systems as tactical weapons, which implies an intent to arm them with lower-yield battlefield nuclear weapons.

Experts say the North with the wording is communicating a threat to proactively use those weapons during conventional warfare to blunt the stronger conventional forces of South Korea and the United States, which keeps about 28,000 troops in South Korea to help deter potential aggression from North Korea.

Kim’s comments were in line with an escalatory nuclear doctrine the North set into law last year, which authorizes preemptive nuclear strikes in situations where it may perceive its leadership as under threat, including conventional clashes.

Photos published by North Korea’s official Rodong Sinmun newspaper showed at least six rockets being fired from launch vehicles lined up in an unspecified coastal forest area.

Kim watched the firings from an observation post along with military officials and his daughter, believed to be named Kim Ju Ae and around 10 years old.

She has appeared at several events tied to his military since first being showcased at an ICBM test launch in November, and analysts believe the events and elevated descriptions of her in state media are meant to show the world he has no intention to voluntarily surrender his nuclear weapons, which he apparently sees as the strongest guarantee of his survival and the extension of his family’s dynastic rule.

Coming off a record year in missile testing, North Korea has conducted additional weapons demonstrations in 2023. Experts say North Korea with its heightened testing activity and threats is trying to claim a dual ability to conduct nuclear strikes against South Korea and the U.S. mainland.

Kim’s campaign is aimed at forcing the United States into accepting the North as a nuclear power and negotiating badly needed economic concessions from a position of strength, analysts say. Diplomacy between the U.S. and North Korea has stalled since 2019.

The South Korean and U.S. militaries will conduct computer-simulated command post training March 13-23 and will resume their largest springtime field exercises, which were last held in 2018. The allies’ regular drills were canceled or scaled back to support diplomacy or because of the COVID-19 pandemic but they renewed them after the diplomacy collapsed and North Korea’s threats and weapons testing escalated.

On Tuesday, Kim Yo Jong, the North Korean leader’s powerful sister and one of Pyongyang’s top foreign policy officials, warned that her country is ready if necessary to take “quick, overwhelming action” in the face of the allies’ expanded drills.

In previous statements, she threatened to turn the Pacific into North Korea’s firing range and repeatedly implied that the North might test-fire an ICBM toward those waters on a standard ballistic trajectory, which would be seen as one of its most provocative weapons demonstrations yet.

All of North Korea’s ICBM tests since 2017 have been conducted on a high angle to avoid the territories of neighbors.