North Korean leader Kim Jong Un oversaw the test-firing Wednesday of a long-range surface-to-air missile at a launch site near its east coast, state media KCNA reported.

The test, aimed at assessing the country's strategic technology for developing a ⁠new type of high-altitude missile, destroyed targets in the air from 124 miles away, ​KCNA said.

Kim also observed construction work at a separate site on an 8,700-ton nuclear-powered submarine capable of launching surface-to-air missiles, KCNA said. It did not identify the location or the date of his visit.

The submarine project is part of the North Korean ruling party's effort to modernize the country's navy, one of five key policies the party is pushing ​to develop its defense capabilities, KCNA said.

Kim was quoted as saying that the ‍all-out development of nuclear capabilities and modernization of the navy are ‌essential and inevitable, while "the present world is by no means peaceful."

Kim also said South Korea's plan for developing ⁠a nuclear ​submarine, agreed with Washington, would further inflame tensions on the Korean Peninsula and poses a risk to ‍national security that requires him to take action.