North Korea fired a ballistic missile into the sea on Tuesday, South Korea's military said, its latest in a series of tests with analysts saying it could have been a submarine-launched weapon.

The "unidentified ballistic missile" was fired from Sinpo into the sea east of the peninsula, Seoul's Joint Chiefs of Staff said in a statement, AFP reports.

"South Korean and US intelligence are closely analysing for additional detail," it added.

Sinpo, where the missile was fired from, is a major naval shipyard and satellite photographs have previously shown submarines at the facility.

The North is known to be developing a submarine-launched ballistic missile (SLBM) and previously carried out an underwater launch, although analysts said that one was likely to have been from a submerged platform rather than a submarine.

"There is a high possibility the North launched an SLBM," said Shin Beom-chul, a researcher at the Korea Research Institute for National Strategy.

It comes after the nuclear-armed North -- which invaded its neighbour in 1950 -- in recent weeks tested a long-range cruise missile, a train-launched weapon and what it said was a hypersonic warhead, sparking global concern.

It also mounted a rare weapons exhibition, showcasing the gigantic international ballistic missile (ICBM) revealed at a night-time military
parade last year.

"The fundamental reason for the North's provocation is because the US is not changing its position on talks," Shin told AFP, adding: "Pyongyang is trying to demonstrate that it can carry out a bigger provocation."

Opening the weapons exhibition, leader Kim Jong Un -- who has overseen rapid progress in the North's military technology, at the cost of international sanctions -- blamed the United States for tensions, dismissing Washington's assertions that it does not have hostile intentions.

GY