South Korea’s news reported that an unspecified ballistic missile was test-fired toward the Sea of Japan by North Korea on Monday, citing the South Korean military. In response, the Japan Coast Guard issued two warnings that two launches were carried out by South Korea.

After the first warning was issued at 07:50 am local time by the Japan coast guard with the second following 10 minutes later, Japan’s Defense Ministry stated that the missiles traveled 350 kilometers with an altitude of 31 miles before plunging into the sea. 

Japan confirmed that both missiles landed outside of the country's exclusive economic zone.

Read next: South Korea eyes 'complete normalization' of military pact with Japan

That comes a week after a ballistic test missile fired by North Korea also landed outside of Japan's exclusive economic zone, and the former's leader Kim Jong-un announced that it was part of a military drill intended to test his country's ability to react to a nuclear attack with nuclear weapons of its own.

According to North Korean media, Kim Jong-un "stressed the need to let service personnel get familiar with any unexpected circumstances and make them more prepared in their active posture of making an immediate and overwhelming nuclear counterattack anytime."

'Freedom Shield 23' to be responded to

These events serve in the light of joint military drills between the US, Japan, and South Korea against the DPRK for regional and nuclear hegemony - more recently, the 'Freedom Shield 23' exercises that took place between March 13 to March 23. 

Read next: DPRK conducts drills to improve nuclear counteroffensive readiness

Tensions on the Korean peninsula have been escalating, as the US and South Korea completed what was described as the largest joint field exercises in five years last week. Earlier this month, Pyongyang said that the "irresponsible acts" of Washington and Seoul will take the region "to a very critical and uncontrollable phase."

This year, the DPRK has conducted nearly 40 test launches, firing approximately 70 missiles, including an intercontinental ballistic missile test in November.

Joint military drills may only increase from here on out. The US and South Korea concluded their six-day war games named the Vigilant Storm in November -- the widest-scale military exercise of its kind, including 240 warplanes conducting 1,600 sorties.

In response, the DPRK said it responded to the war games by hitting key enemy targets in an exercise.