Seoul has called North Korea's actions as extremely inappropriate after it launched "super large missiles" into the ocean as the world is plagued by a pandemic.

On Sunday, North Korea launched what appeared to be two ballistic short-range missiles off its east coast, the fourth such test this month as the world battles the deadly disease.

Joint staff commanders of South Korea said a single projectile was launched on Sunday morning, but revised their report to say that two suspected missiles were fired from the town of Wonsan in the north. These projectiles later landed in the waters between Japan and the Korean Peninsula.

The series of military exercises comes as a lengthy pause in disarmament talks with the United States drag on, and in spite of recent Washington overtures promising support to combat the pandemic.

The defense ministry of Tokyo said the projectiles fell short of the waters of Japan and the exclusive economic zone of the region.

The nuclear-armed North has yet to make a comment on the missiles on Sunday, but this month attributed its three other tests - all of which landed in the Sea of Japan - to exercises for "long-range artillery."

In recent weeks, the North Korean military has launched a series of missiles and shells of artillery in an apparent effort to improve its military potential in the midst of failed nuclear talks with the US.

After the collapse of a second Summit between North Korean leader Kim Jong Un and US President Donald Trump in early 2019, the talks have stalled.

Pyongyang said United States President Donald Trump sent Kim a personal letter a week ago, seeking to maintain good ties and offer help in combating the outbreak.

North Korea has shut its borders in an effort to shield the hermit regime from the coronavirus, and is among the few remaining nations yet to record a disease case that has claimed the lives of nearly 34,000 people around the world.

But it is widely believed that the deadly virus has entered the country, with government and medical authorities warning that it may cause a lot of damage to North Korea due to its poor health infrastructure and rising poverty.

As per latest data provided by Reuters, Pyongyang's total number of missile launches this month has reached 10. The country has broken its own record of most number of missile tests in a single month.