Seoul: A day after the start of an important military exercise between South Korea and the US, North Korea launched two short-range ballistic missiles from its west coast into the Sea of Japan on Tuesday, according to the South Korean military, reported Kyodo News.

South Korea's Joint Chiefs of Staff was cited as saying in the daily that the missiles launched from Jangyon in South Hwanghae Province between 7:41 am and 7:51 am travelled 620 kilometres.

According to the North's state-run media and the JCS, the most recent launches came after North Korea launched two cruise missiles on Sunday from a submarine off the coast of Sinpo in the country's east.

On Thursday, Pyongyang launched at least one short-range ballistic missile into the Yellow Sea from the western city of Nampo, denouncing US-South Korean military manoeuvres as "rehearsals" for war and invasion. Pyongyang had previously warned against the new exercise.

According to the South Korean and American forces, the 11-day Freedom Shield exercise--the first such springtime exercise in five years--is to improve response capabilities in light of North Korean nuclear and missile threats, read a report in Kyodo News.

Japanese Prime Minister Fumio Kishida told reporters in Tokyo that he has not heard of any harm occurring in Japan. Separately, Yasukazu Hamada, Japan's defence minister, stated that based on information already available, the missiles had not come down inside Japan's exclusive economic zone.

Ned Price, a spokesperson for the US State Department, justified the Freedom Shield exercise on Monday by claiming it is "purely defensive in character."

Following the most recent missile launches, the US Indo-Pacific Command declared that North Korea's "illegal" development of WMD and ballistic missiles had a "destabilising influence" on the region.

The command, referring to South Korea by its official name, said in a statement: "The US commitments to the defence of the Republic of Korea and Japan are firm."

The JCS of South Korea called North Korea's recent ballistic missile tests "severe provocations" not only to the peace and stability of the international community but also to the Korean Peninsula. It asked Pyongyang to stop right away.

The Central Military Commission of the ruling Workers' Party of Korea met on Sunday, according to the official Korean Central News Agency of the North, and took "major practical steps" for more effective, potent, and offensive employment of the nation's war deterrent weapons.

According to KCNA, the meeting, led by leader Kim Jong Un, deliberated on steps to take in response to the current scenario, in which the United States and South Korea's provocations are crossing a red line, Kyodo News reported.