SEOUL, Aug. 19 (UPI) — North Korean leader Kim Jong Un said a U.S.-South Korea joint military exercise showed their “will to ignite a war” and called for the rapid expansion of Pyongyang’s nuclear capabilities, state media reported Tuesday.

“The U.S.-ROK intensified military nexus and the muscle-flexing are the most obvious manifestation of their will to ignite a war,” Kim said, according to state-run Korean Central News Agency.

Kim made the remark as he inspected the North’s first 5,000-ton destroyer, the Choe Hyon, at Nampo Shipyard on Monday — the same day that the United States and South Korea kicked off an 11-day joint military exercise.

The annual summertime Ulchi Freedom Shield includes live field maneuvers, computer simulation-based command post exercises and related civil defense drills. Some 21,000 troops, including 18,000 South Korean personnel, are participating this year.

Kim said the allies’ joint drills “have always been provocative and dangerous in their nature but the gravity is increasing,” according to KCNA.

“The security environment around the DPRK is getting more serious day by day and the prevailing situation requires us to make a radical and swift change in the existing military theory and practice and rapid expansion of nuclearization,” he said.

The Democratic People’s Republic of Korea is the official name of North Korea.

During his visit to Nampo Shipyard, Kim received a report on the Choe Hyon’s various weapons systems and expressed “satisfaction over the fact that the major tasks for making the navy high-tech and nuclear-armed are progressing on a stage-by-stage basis as planned,” KCNA said.

The destroyer, which was launched in April, is armed with a wide range of weapons including anti-aircraft missiles, 127mm naval guns and nuclear-capable cruise and ballistic missiles, according to North Korean reports.

A second destroyer, named the Kang Kon, was unveiled in May but suffered a launch accident that left it listing on its side.

Kim, who was in attendance at the launch, called the mishap a “criminal act” and warned of serious consequences for those found responsible.

The ship was repaired and relaunched in June, although analysts have questioned whether it is fully operational. At that ceremony, Kim vowed to “commission two destroyers of the same class or higher into the navy every year.”

Kim’s latest comments come as South Korean President Lee Jae Myung is making a push to improve inter-Korean relations.

In a speech Friday marking the 80th anniversary of Korea’s liberation from Japanese colonial rule, Lee vowed to “respect” North Korea’s political system and said Seoul would not pursue “unification by absorption.”

“We have no intention of engaging in hostile acts,” Lee said. “Going forward, our government will take consistent measures to substantially reduce tensions and restore trust.”

North Korea has so far rebuffed Lee’s overtures. Kim Yo Jong, the influential sister of the North Korean leader, recently condemned Seoul’s “blind trust” in its military alliance with Washington and mocked reconciliation efforts as “nothing but a pipedream.”