The Japanese Coast Guard and South Korean military reported on Saturday that North Korea fired at two projectiles toward the East Sea that landed outside Japan's exclusive economic zone.
The apparent short-range missiles were fired from North Pyongan province, South Korea's Joint Chiefs of Staff (JCS) said.
"Such military action by North Korea is highly inappropriate at a time when COVID-19 is causing difficulties worldwide," the JCS said, calling for an "immediate stop."
The nuclear-armed North carried out similar launches on two other occasions in March. Japan said those projectiles appeared to be ballistic missiles.
The latest trio of launches comes as an extended hiatus in disarmament talks with the United States drags on. Both Washington and Beijing have called on Pyongyang to halt its nuclear and missile programs and return to talks.
Pyongyang has been banned from testing ballistic missiles by UN resolutions, and international sanctions aim to deter it from continuing to develop its rockets.
International concern over North Korea grew in 2019 after the country imposed a year-end deadline for the United States to offer sanctions relief and threatened to send a "Christmas gift," widely seen to mean a weapons test, if its demands went unfulfilled.
North Korean leader Kim Jong Un said the world would see a "new strategic weapon" in the near future, in a message on January 1.
US President Donald Trump has demanded that North Korea give up all its nuclear weapons and production facilities in exchange for the lifting of sanctions.
Supreme People's Assembly meeting coming up?
North Korea also announced that it will hold a session of its legislature, the Supreme People's Assembly. Analysts have said that would involve gathering almost 700 of the country’s leaders in one spot even as the coronavirus spreads around the world.
"If it goes ahead, it would be the ultimate show of [North Korea's] confidence in managing the coronavirus situation," Rachel Minyoung Lee, of the North Korea monitoring website NK News, said on Twitter this week.