North Korea fires 'unidentified projectile': South Korea military

North Korea fired at least one "unidentified projectile" over the Sea of Japan on Thursday, Seoul's military said, with Tokyo reporting it as a possible launch of a ballistic missile.

"North Korea fires unidentified projectile toward East Sea," South Korea's Joint Chiefs of Staff said in a message to news organisations, referring to the body of water also known as the Sea of Japan.

The latest launch came a day after Pyongyang accused Japan of "transformation into a war state" as Tokyo beefs up its military stance in the Pacific.

"Something that may be a ballistic missile has been launched from North Korea," Japan's defence ministry posted on X.

Tokyo's Defence Minister Shinjiro Koizumi said this week the country's military needs to be boosted with a "sense of urgency and crisis", as a new government assessment warned of growing threats from China, Russia and North Korea.

Kim Yo Jong -- the powerful sister of leader Kim Jong Un -- said in a statement carried by North Korean state media on Wednesday that Pyongyang's "leadership will set up additional military options which are obviously due to Japan's transformation".