South Korea called an emergency National Security Council meeting where members denounced the launch as a clear violation of U.N. Security Council resolutions.
North Korean leader Kim Jong Un said his country will never abandon the nuclear weapons it needs to counter the United States, which he accused of pushing to weaken the North's defenses.
The north's stockpile of bullets and artillery rounds are compatible with Russia's weapons, but may be lower-quality. Transferring anything more powerful would get much more complicated.
While Washington and Seoul describe their exercises as defensive, North Korea portrays them as invasion rehearsals and has used them to justify its nuclear weapons and missiles development.
The North's official news agency also reported that Kim's sister blamed the COVID outbreak on leaflets flown from across the border from South Korea, while warning of deadly retaliation.
North Korea on Sunday slammed the United States, South Korea and Japan for pushing to boost their trilateral military cooperation, warning it would reinforce its military capability.
The barrage of eight missiles test-fired over 35 minutes extends a streak in weapons demonstrations this year that U.S. and South Korean officials say may culminate with a nuclear test explosion.
After saying there were no cases, officials on May 12 announced an outbreak. But without an adequate supply of tests, some say North Korea is "flying blind." And it still doesn't have vaccines.