North Korea on Tuesday launched another projectile in the direction of the Sea of Japan, which Seoul and Tokyo suspect to be a ballistic missile.

It came just six days after Pyongyang tested what it claimed was a new hypersonic missile.

"Our military detected a projectile presumed to be a ballistic missile launched by North Korea from inland into the East Sea around 07:27 today," the South Korean Joint Chiefs of Staff, which had earlier noted an "unidentified projectile," said in a statement.

"The ROK (South Korea) and US intelligence agencies are conducting detailed analysis for additional information," it added.

The Japanese Coast Guard also said an object, "potentially" a ballistic missile, had been launched from North Korea, and that it had "possibly" already dropped into the water, although without specifying where.

Japanese Prime Minister Fumio Kishida told reporters it was “extremely regrettable that North Korea repeatedly launches missiles.”