North Korea tests submarine-launched cruise missile, state media says

North Korea's military again tested an in-development strategic cruise missile, launching it from a submarine on Sunday, state media said.

The secretive country's leader, Kim Jong Un, supervised the test along with other military officials, the official Korean Central News Agency said on Monday. The test was part of his plan to continue "accelerating the nuclear weaponization of our navy," KCNA reported.

A submarine fired a Pulhwasal-3-31, the same type of strategic missile the country said it test-fired from land last week, KCNA reported.

"Kim Jong Un expressed great satisfaction over the result of the test," state media said.

Photos published on Monday by state media appeared to show Kim watching the tests from a vantage point above a body of water. In one photo released by KCNA, Kim appeared to be pointing at a missile in mid-flight.

The missile flew over the East Sea and struck an island target, state media said.

The launch followed another Pulhwasal-3-31 missile test-fire on Wednesday, according to state media. As the country announced both tests, state media noted that neither had an effect on "neighboring" countries.

"The test-fire had no impact on the security of a neighboring country and has nothing to do with the regional situation," KCNA reported on Monday.

The launch comes amid growing cooperation between the United States, South Korea and Japan, with the three countries saying they're sharing real-time updates and analysis on military activity in the region.

The U.S. State Department on Wednesday had called for North Korea to "refrain from further provocative, destabilizing actions and return to diplomacy."

"We are eager to engage in substantive discussions on identifying ways to not just manage military risk but create lasting peace on the Korean Peninsula," Vedant Patel, a spokesperson, said during a press briefing, "as well as our continued stated goal of the complete denuclearization of the Korean Peninsula."

North Korea on Monday said Kim told his military advisors that "nuclear weaponization of the navy is an urgent task of the times."

Kim "set forth the important tasks arising in realizing the nuclear weaponization of the navy and expanding the sphere of operation of the state nuclear deterrence in a diversified way," KCNA said.

ABC News' Will Gretsky contributed to this report.