North Korean state media on Monday said dictator Kim Jong-un personally oversaw drills on Saturday and Sunday that simulated his regime’s “war deterrence and nuclear counterattack capability,” meaning a nuclear attack on the United States and South Korea.

The drill included the troubling launch of an alleged solid-fueled ballistic missile from a hidden underground silo.

“The drill also aimed to demonstrate our tougher will to make an actual war response and send a stronger warning to the enemy who expand their war drills for aggression,” said North Korea’s KCNA news service.

This was a reference to the joint U.S.-South Korea military drills in progress over the weekend, including aerial exercises that paired South Korean fighters with American B-1B long-range bombers. North Korea consistently denounces such training exercises as “provocations.”

The North Korean missile launched on Sunday reportedly carried a mock nuclear warhead and flew about 500 miles, which would be good enough to hit South Korea in a real engagement. North Korean state media described the weapon as a solid-fueled KN-23 short-range ballistic missile and displayed photos of it rising from an underground silo. 

Solid-fueled missiles can be prepared for launch much more quickly than those using liquid fuel, and an underground launch silo would mean preparations for launch could be conducted in secrecy. Defense analysts believe North Korea has constructed several underground silos, although their readiness for launch is unknown.

The test launch was convincing enough for the U.S., South Korea, and Japan to condemn it as a threat to peace on the peninsula. The U.S. Indo-Pacific Command issued a statement on Saturday that said Pyongyang’s recent missile launches “highlight the destabilizing impact of its unlawful WMD and ballistic missile programs.”

North Korean state media pictured Kim attending the missile launch with his daughter Kim Ju-ae, believed to be roughly ten years old. Kim Ju-ae made her public debut in November after a lifetime of secrecy and has become a fixture at her father’s public appearances, including military events. This has led to speculation that Kim will name her as his successor, which would make her the first female leader in the history of the North Korean dictatorship.

KCNA published a story on Saturday claiming that over 800,000 “working young people” have eagerly volunteered to fight the United States in a “campaign to defend the country and annihilate the enemy.”

KCNA portrayed this ostensible rush to enlistment as a necessary show of strength against “moves to provoke a nuclear war by America and the South Korean puppets.”