North Korea (DPRK) has reportedly fired a KN-11 ballistic missile from a submarine towards Japan.

The missile test fire follows two days after South Korea and US Combined Forces Command (CFC) started the annual Ulchi Freedom Guardian (UFG) exercise to protect the region and maintain stability on the Korean peninsula.

A statement from US Strategic Command said the missile was fired from Sinpo, a coastal city in North Korea, and travelled around 500km before landing in the Sea of Japan.

"We remain prepared to defend ourselves and our allies from any attack or provocation."

South Korea’s Joint Chiefs of Staff (JCS) said that the latest test was seen as ‘an improvement’ over earlier missile launches.

Japanese Prime Minister Shinzo Abe confirmed that the missile entered the country’s air defence identification zone.

Condemning the missile test firing, Abe was quoted by CNN as saying: "This is a threat to Japan's security and an unforgivable reckless act that significantly damages the peace and stability of the region."

Since the beginning of this year, North Korea has conducted a series of missile launches, even after new sanctions were imposed by the UN Security Council.

Pentagon spokesman Gary Ross was quoted by The Guardian as saying: “We remain prepared to defend ourselves and our allies from any attack or provocation.

“We call on North Korea to refrain from actions that further raise tensions in the region and focus instead on taking concrete steps toward fulfilling its commitments and international obligations.”