Speculation had mounted that the North could carry out a sixth nuclear test or another missile launch to mark the 85 years since the founding of its army on Tuesday.
Instead, the North's state-run KCNA news agency said the Korean People's Army marked the anniversary with a "successful largest-ever artillery drill" under the orders of Supreme Commander Kim in the eastern port city of Wonsan.
"Submarines rapidly submerged to make torpedo-attacks at the enemy warships" while aircraft dropped bombs.
"The brave artillerymen are mercilessly striking the targets, the way they fire is liberating and their shots are very accurate," KCNA cited Kim as saying.
After the drill, the troops pledged their loyalty to Kim, vowing to "turn into 10 million guns and 10 million bombs" to defend him.
Pyongyang's rhetoric always intensifies in the spring, when Seoul and Washington hold joint military drills which it sees as rehearsals for an invasion.
The Rodong Sinmun -- the official mouthpiece of the ruling Workers' Party of Korea -- carried several photos of the drill in a three-page spread.
The front page showed Kim arriving at the site in his black Mercedes Benz with hundreds of tanks lined up. More than 30 pictures showed the drill in detail with Kim roaring with laughter as he watched artillery fire.
North Korea has ambitions to build a nuclear-tipped missile capable of reaching the US mainland. Tensions have soared in recent months as it carried out a string of missile tests that sparked tit-for-tat sabre-rattling between it and Washington.
Washington has sent the aircraft carrier USS Carl Vinson to the Korean peninsula, where it is expected to arrive later this week for a joint naval exercise with South Korea.
The North has labeled the Vinson's deployment "undisguised military blackmail" and has threatened to "bury it at sea".