North Korean leader Kim Jong Un at an official meeting. (Kcna/Reuters)

North Korea said Wednesday that it practiced trying to blow up South Korean ports and airports with nuclear warheads during its most recent ballistic missile launches, the latest sign of Pyongyang’s anger over attempts to contain it.

North Korea launched three missiles — two short-range Scuds and one medium-range Rodong — from a launch site south of Pyongyang early Tuesday. They flew about 350 miles across the peninsula to land in the sea off the eastern coast, and South Korean military officials said the missiles had the potential to hit even the southernmost parts of their country.

The launches were part of a drill overseen by Kim Jong Un, the third-generation leader of North Korea who bears the official title of “Supreme Commander of the Korean People’s Army.”

The drill rehearsed “making preemptive strikes at ports and airfields in the operational theater in South Korea, where the U.S. imperialists’ nuclear war hardware is to be hurled,” the North’s official Korean Central News Agency said Wednesday. 

In response to the North’s provocations this year — a nuclear test in January and the steady stream of missiles that have followed it — South Korea has agreed to host a sophisticated antimissile system despite strong objections from China, a key trading partner.

The United States and South Korea this month finalized the details for deploying a terminal high-altitude area defense (THAAD) battery to South Korea that would be operated by U.S. forces stationed there. It is designed to intercept incoming missiles.

Han Min-goo, the South’s defense minister, told lawmakers in an emergency session Tuesday afternoon that the North’s missiles constituted a “sort of protest” against the planned THAAD deployment.

The decision also has been controversial in South Korea, particularly in the rural area of Seongju, which has been chosen as the site for the battery. Residents pelted the South Korean prime minister with eggs last week when he visited the area, about 130 miles southeast of Seoul, to try to alleviate their concerns that they would become a target for North Korea.

The North has unleashed a steady stream of invective over the South Korean government’s increasingly assertive response, and it has boasted of technological breakthroughs in its nuclear weapons program.

Tuesday’s drill simulated detonating “nuclear warheads mounted on the ballistic rockets at the designated altitude over the target area,” KCNA said.

North Korea has proved it has nuclear devices and has also shown advances in its missile program, although progress has not always been smooth. Most of the six intermediate-range Musudan missile tests carried out in recent months have been failures.

Despite North Korea’s boasts, there is considerable doubt about whether North Korea has mastered the next, difficult steps: making nuclear warheads small enough to mount on a missile, and then being able to deliver the blow. While many analysts, and a considerable number of U.S. officials, think that it is just a matter of time until the North figures it out, no evidence yet suggests that the country’s nuclear weapons program is at such a level.

But North Korea has continued to pump out statements that increase tension on the peninsula, where the two sides remain technically at war, more than 60 years after the Korean War.

“Kim Jong Un expressed great satisfaction over the successful drill,” the KCNA statement said, and he praised the soldiers for being “fully ready to carry out any order issued all of a sudden.”