In its previous weapons test on Nov. 28, North Korea launched two rockets from its east coast, firings that were overseen by Mr. Kim, the country’s leader. South Korea later said the two short-range projectiles were fired from what North Korea called a “super-large multiple rocket launcher,” a new weapon the North had developed to target South Korean and United States military bases farther from North Korea’s border with the South.

But North Korea had been refraining from any weapons tests since Mr. Kim told a meeting at the end of December that he had all but abandoned hopes for diplomacy with Washington and ordered his country to brace for a prolonged standoff with the United States and endure sanctions. In that meeting, Mr. Kim also said his country no longer felt bound by its self-imposed moratorium on testing nuclear weapons and long-range ballistic missiles and that the world would witness a new strategic weapon “in the near future.”

Mr. Kim has also been keeping himself largely from public view as he locked his country down to prevent the spread of the coronavirus outbreak from neighboring China. On Friday, he appeared to resume his public activities, inspecting a joint strike drill of units of the North Korean People’s Army, according to the state-run media.

The military drill coincided with the anniversary of Mr. Kim’s summit last year with President Trump in Hanoi, Vietnam. The summit collapsed over differences over how fast North Korea would roll back its nuclear weapons program and when Washington should ease sanctions.

The Monday launch came three days after Mr. Kim fired one of his closest aides for corruption during a meeting of the Political Bureau of his Workers’ Party. The meeting focused on “enforcing top-class anti-epidemic measures to contain the viral epidemic spreading rapidly across the world,” although the North itself has not reported any cases of the new coronavirus.