The new firings came as the UN Security Council met in New York to discuss the launch of another North Korean missile that had flown over Japan two days earlier.
According to the South Korean army, two short-range missiles were launched Thursday morning from around Pyongyang towards the Sea of Japan. The Japanese coast guard confirmed having detected these projectiles.
This sixth launch in less than two weeks is "absolutely unacceptable", immediately reacted Japanese Prime Minister Fumio Kishida.
On Tuesday, a Hwasong-12 missile flew over Japan and traveled about 4,600 km, probably the longest distance Pyongyang has ever reached in its tests, according to Seoul and Washington.
It was the first time in five years that a North Korean projectile passed over Japanese territory.
North Korea, which in September adopted a new doctrine making its status as a nuclear power "irreversible", this year stepped up its firing and launched an intercontinental ballistic missile (ICBM) for the first time since 2017.
The firings are "the Korean People's Army's just retaliation against the joint military maneuvers between South Korea and the United States that are causing an escalation of military tensions on the Korean Peninsula," the North Korean ministry said Thursday. Korean in a statement.
Following Tuesday's launch, Washington called for an emergency meeting of the United Nations Security Council. But China, an ally and economic partner of North Korea, also blamed the United States.
- China blames Washington -
Pyongyang's missile tests are "closely linked" to US-South Korean military exercises, Chinese deputy ambassador to the United Nations Geng Shuang told the council.
He accused Washington of "poisoning the regional security environment".
Seoul, Tokyo and Washington have stepped up joint military maneuvers in recent weeks, including anti-submarine drills and large-scale naval maneuvers.
On Wednesday, South Korea and the United States fired five ballistic missiles - one of which crashed after launch - at fictitious targets in the Sea of Japan. And the day before, the air forces of the two countries had conducted shooting exercises in the Yellow Sea.
Seoul also announced the return to the region of the American nuclear-powered aircraft carrier USS Ronald Reagan, which carried out exercises with the South Korean navy in September.
The Security Council meeting was supported by France, the United Kingdom, Albania, Norway and Ireland.
US Ambassador to the UN Linda Thomas-Greenfield denounced "a clear effort by China and Russia to reward (North Korea) for its bad actions", and called for tougher sanctions against Pyongyang .
In May, Beijing and Moscow vetoed a Security Council resolution imposing new sanctions on North Korea, after the body unanimously adopted heavy sanctions in 2017.
According to analysts, the regime of North Korean leader Kim Jong Un is seizing the opportunity of the deadlock at the UN to push its weapons tests ever further.
Seoul and Washington expect North Korea to resume its nuclear tests, which have been interrupted since 2017, probably after the Chinese Communist Party congress which begins on October 16.
"At this point, for Kim to back down and stop the provocations would seem counterproductive to his interests. Not to mention the amount of resources wasted conducting these weapons tests," analyst Soo Kim told AFP. at the RAND Corporation.
"We are definitely in a cycle of armed provocation," she said.