North Korea says a ballistic missile test was a rehearsal for attacks against South Korean ports and airports that have U.S. nuclear warheads as it defiantly rejects efforts to contain its atomic weapons program.

North Korea fired three missiles — two Scuds and a Rodong — on Tuesday, officials said. Two of the missiles flew about 310 to 372 miles across the country before landing off the east coast in the Sea of Japan, South Korea’s military said, adding the distance flown by the third was still being analyzed.

North Korean leader Kim Jong Un supervised the launches and gave the order to begin, according to the state-run Korean Central News Agency. He later “expressed great satisfaction over the successful drill,” it said.

“The drill was conducted by limiting the firing range under the simulated conditions of 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,” KCNA said Wednesday.

“And it once again examined the operational features of the detonating devices of nuclear warheads mounted on the ballistic rockets at the designated altitude over the target area,” it added.

The official ruling Workers’ Party newspaper Rodong Sinmun carried photographs of a ballistic missile launch along with Kim apparently observing it — a strategic map of the peninsula titled “the strategic forces’ firepower strike plan” sprawled in front of him.

Neither report mentioned the date of the drill.

Tuesday’s salvo was widely believed to be North Korea’s answer to the July 8 agreement by the U.S. and South Korea to deploy a Terminal High-Altitude Area Defense system, known as THAAD, on the divided peninsula to counter the growing missile threat from the North.