North Korean leader Kim Jong Un supervised drills involving the firing of nuclear-capable multiple rocket launchers to show the country’s ability to carry out a preemptive attack on rival South Korea, state media reported Friday.

North Korea has simulated nuclear strikes on South Korea numerous times, but the latest drills came after animosities on the Korean Peninsula rose over North Korea’s recent failed spy satellite launch.

The North’s official Korean Central News Agency reported that the rocket firing drills were meant to demonstrate North Korea’s resolve not to hesitate in launching a preemptive strike on South Korea if threatened. It cited Kim as saying that the drills “will serve as an occasion in clearly showing what consequences our rivals will face if they provoke us.” Photos showed Kim watching from a distance as at least 18 projectiles were launched.

KCNA suggested the drills came as response to a South Korean aerial exercise performed hours before North Korea’s failed attempt to place its second spy satellite into orbit on Monday night.The launch attempt drew strong condemnation from South Korea, the U.S. and others because the U.N. bans any satellite launches by North Korea, viewing them as covers for testing missile technologies. North Korea reacted angrily, arguing that it has the sovereign right to launch satellites.

Also this week, North Korea flew hundreds of huge balloons into South Korea carrying manure and other trash, and allegedly jammed GPS navigation signals in the South. There were no reports of any substantial damage.

South Korea’s Unification Ministry responded in a statement Friday that North Korea must stop “absurd, irrational provocations directed at us” or face unspecified “unbearable” consequences. Ministry spokesperson Kim Inae said separately that South Korea “strongly condemns” North Korea for threatening preemptive strikes against the South.

Observers speculate the South Korean retaliatory steps could include a resumption of loudspeaker broadcasts into North Korea that include criticism of its human rights situation, world news and K-pop songs. North Korea is extremely sensitive to such broadcasts because most of its 26 million people are not allowed access to foreign TV and radio programs.

The North Korean firing exercises appeared to be short-range ballistic missile test-launches that South Korea detected from North Korea’s capital region on Thursday. Experts say North Korea’s large artillery rockets blur the boundary between artillery systems and short-range ballistic missiles because they can create their own thrust and are guided during delivery.

Since the start of 2022, North Korea has been engaged in a series of provocative weapons tests to increase its nuclear capabilities to cope with what it calls an intensifying U.S. military threat. Foreign experts say North Korea eventually aims to use its larger nuclear arsenal to wrest greater concessions from the U.S. when diplomacy resumes.