The launches on Sunday came days after North Korea showed apparent progress in the construction of its first nuclear-powered submarine.

This picture taken on Sunday and released by North Korean state media shows a long-range strategic cruise missile launching drill.AFP Contributor#AFP / AFP - Getty Images

North Korea said Monday that it fired long-range strategic cruise missiles into the sea to test the country`s nuclear deterrence, days after it showed apparent progress in the construction of its first nuclear-powered submarine.

The launches on Sunday were the latest weapons display by North Korea ahead of its planned ruling Workers` Party congress early next year. Keen outside attention on the congress, the first of its kind in five years, will be on whether North Korean leader Kim Jong Un will establish new priorities in relations with the U.S. and respond to Washington`s calls to resume long-dormant talks.

The official Korean Central News Agency reported that Kim expressed "great satisfaction" over Sunday`s launches, which occurred off the country`s west coast. It said Kim noted that testing the reliability of North Korea`s nuclear deterrence and demonstrating its might are "just a responsible exercise of the right to self-defense and war deterrence" in the face of external security threats.

South Korea`s Joint Chiefs of Staff said it was aware of several cruise missile launches made from North Korea`s capital region on Sunday morning. It said South Korea maintains a readiness to repel any potential North Korean provocations through its alliance with the United States.

U.N. Security Council resolutions prohibit North Korea from launches involving its huge stockpile of ballistic missiles. Its cruise missile tests are not banned, but they still pose a threat to the U.S. and South Korea because they are highly maneuverable and fly at low altitudes to avoid radar detection. Analysts say North Korea would aim to use cruise missiles to strike U.S. warships and aircraft carriers in the event of conflict.

Last week, North Korea test-launched new anti-air missiles off its east coast and displayed photos showing a largely completed hull of a developmental nuclear-powered submarine. North Korea implied that it would arm the submarine with nuclear missiles.

A nuclear-powered submarine is among a slew of sophisticated weapons systems that Kim has vowed to introduce to cope with what he describes as U.S.-led security threats. Some experts say North Korea`s recent alignment with Russia - including sending thousands of troops and military equipment to support President Vladimir Putin`s war in Ukraine - may have helped it to receive crucial technologies in return.

North Korea has focused on weapons-testing activities to expand its nuclear arsenal since Kim`s high-stakes nuclear diplomacy with U.S. President Donald Trump collapsed in 2019.

But in an apparent response to Trump`s repeated outreach, Kim suggested in September that he could return to talks if the U.S. drops "its delusional obsession with denuclearization" of North Korea. Experts say Kim might think his enlarged nuclear arsenal would give him greater leverage to wrest concessions in potential talks with Trump.