South Korea's military earlier said North Korea fired two projectiles, likely from the same "super-large" rocket launcher, on Thursday. It expressed "strong regret" over the launches and urged North Korea to stop escalating tensions.
On Friday, the North's Korean Central News Agency confirmed the launches were made with the presence of leader Kim Jong Un and other top officials.
"The volley test-fire aimed to finally examine the combat application of the super-large multiple launch rocket system proved the military and technical superiority of the weapon system and its firm reliability," KCNA said.
It said Kim expressed "great satisfaction" over the results of the test-firing.
Analyst Kim Dong-yub at Seoul's Institute for Far Eastern Studies said North Korea appears to be entering the stage of mass-producing and deploying the rocket launcher. He wrote on Facebook that the weapons system may already have been deployed.
Thursday's firing was the fourth test-launch of the rocket launcher since August.
Some experts say the flight distance and trajectory of projectiles fired from the launcher show they are virtually missiles or missile-classed weapons. The projectiles fired Thursday flew about 380 kilometers (235 miles) at a maximum altitude of 97 kilometers (60 miles), according to South Korea's Joint Chiefs of Staff.
Japanese Prime Minister Shinzo Abe on Thursday called the projectiles ballistic missiles.
North Korea has fired other new weapons in recent months in what some experts say is an attempt to wrest concessions from the United States in stalled nuclear diplomacy while upgrading its military capabilities.
A U.S.-led diplomacy aimed at persuading North Korea to scrap its nuclear program in return for political and economic benefits remains largely stalemated since the February collapse of a summit between Kim and President Donald Trump in Vietnam.
Most of the North Korean weapons tested since the Vietnam summit were short-range. Attention is now on whether North Korea resumes nuclear and long-range missile tests if Trump fails to meet a year-end deadline set by Kim for Washington to offer new proposals to salvage the negotiations.
Trump considers North Korea's self-imposed moratorium on nuclear and intercontinental ballistic missile tests a major foreign policy win.