SEOUL, South Korea — North Korean leader Kim Jong Un commissioned his second naval destroyer and called for building a more reliable nuclear deterrent, state media reported Monday, as the U.S., South Korea and Japan began a trilateral military exercise he views as a security threat.

The development comes as North Korea is dialing up pressure on the U.S. after rebuffing President Donald Trump’s decision to scale back a major military drill with South Korea in a conciliatory step toward Kim. Observers say North Korea wants to wrest bigger U.S. concessions.

The destroyer Kang Kon was commissioned into North Korea’s navy in the eastern port city of Wonsan on Sunday at a ceremony attended by Kim and his teenage daughter whom South Korea’s spy service calls his likely heir. North Korean state media photos showed the girl dressed in a white dress and blazer walking alongside her father on a red carpet, touring the warship and posing with sailors together.

The ship and the Choe Hyon, commissioned in June, are both 5,000-ton destroyers equipped with nuclear-capable missiles, making them North Korea’s most advanced warships.

In a speech at the ceremony, Kim said the destroyers’ back-to-back commissionings instilled fear in the enemies as the nuclear armament of North Korea’s navy made it possible to exercise its nuclear deterrent in a more diversified, practical manner.

“Concerns of the enemies will be surely deepened,” Kim said. “We must establish more clearly a powerful and reliable nuclear war deterrent, to put into practice the diverse and effective operation of our nuclear combat systems and further strengthen our military activities for maritime defense and war deterrence.”

On Monday, the U.S., South Korea and Japan were set to kick off their five-day Freedom Edge exercise in the waters off South Korea’s southern Jeju island. South Korea’s military recently said the exercise is defensive in nature is meant to respond to North Korea’s nuclear threats.

Last week, North Korea’s Foreign Ministry accused the U.S. of more clearly expressing its confrontational posture against the North. It cited the Freedom Edge exercise and U.S. officials’ reported comments that the U.S. remains committed to the complete denuclearization of North Korea.

On Aug. 21, the U.S. and South Korean militaries ended their annual Ulchi Freedom Shield exercise six days earlier than originally planned, after Trump said he had ordered the Pentagon to “substantially reduce” the drill. Trump cited what he described as a good relationship with Kim, who views the drill as an invasion rehearsal.

But Kim’s sister and senior official, Kim Yo Jong, shrugged off Trump’s outreach, saying just shortening the drill won’t change its “provocative, aggressive nature.” North Korea launched about 10 short-range ballistic missiles toward the sea, apparently delivering on its previous threat to respond to the U.S.-South Korean drill.

Kim Jong Un has previously said he could return to talks if the U.S. drops its “hostile policy” against North Korea and respects what he calls North Korea’s status as a nuclear state.

Kim and Trump’s earlier diplomacy collapsed in 2019 due to disputes on how much economic benefits North Korea should get in return for a limited denuclearization step. Now with his advancing nuclear program and deepened ties with Russia and China, experts say Kim has greater leverage than before.