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.