The missiles flew 1,500 km (930 miles) before hitting their targets and falling into the country's territorial waters during the tests held on Saturday and Sunday, KCNA said.
The development of the missiles provides "strategic significance of possessing another effective deterrence means for more reliably guaranteeing the security of our state and strongly containing the military maneuvers of the hostile forces," added the news agency.
North Korea, which has conducted many missile tests in recent years, restarted those tests after denuclearization talks with the United States came to a halt.
Former US President Donald Trump tried to reach an agreement with North Korea while in office. Kim and Trump met in Hanoi in 2019 for a summit that left nuclear talks at a standstill.
The pair had met three times since June 2018 but made little progress towards denuclearization.
The new Biden administration reached out to North Korea but the country did not respond to those overtures.
In Biden’s first policy speech to Congress, he said nuclear programs in North Korea and Iran posed threats that would be addressed through “diplomacy and stern deterrence”.
Responding to that speech, North Korea dismissed the idea of talks with Washington, saying Biden’s speech was “intolerable” and “a big blunder."
In June, Kim said that North Korea should prepare for both dialogue and confrontation with the United States.