Kim Jong-un oversees test of surface-to-sea missile

North Korean leader Kim Jong-un has overseen the test of a new surface-to-sea missile and visited a major munitions factory, where he called for a boost in weapons production, state media says.

North Korea launched multiple cruise missiles off its east coast on Wednesday, South Korea's military said, the latest of multiple such tests in recent weeks before an April general election in South Korea.

Kim said South Korea is violating the North's sovereignty by insisting on a "Northern Limit Line" (NLL), the maritime demarcation line between the two Koreas, state media KCNA said.

Kim gave orders to strengthen military readiness in the waters north of Yeonpyeong Island and to the west of the Korean peninsula, in the region of the NLL, KCNA said.

"It is not important how many lines exist in the West Sea of Korea... when the enemy intrudes into the maritime border recognised by us, we will regard it as an encroachment upon the sovereignty of the DPRK and an armed provocation against it," Kim said, according to KCNA.

The new missile, called Padasuri-6, or Sea Eagle-6, flew over the sea and hit its intended target, KCNA added.

Kim also inspected a "major" munitions factory and learned in detail about the modernisation of production, the state media said.

The leader of the reclusive state also stressed the factory's role in bolstering North Korea's armed forces and laid out tasks to improve the quality of munitions and increase production as "required by the prevailing situation and the developing revolution", KCNA said.

Kim's visit to the munitions factory comes as the United States and its allies have accused North Korea of trading arms with Russia.

The White House last month said Russia had recently used short-range ballistic missiles (SRBMs) sourced from North Korea to conduct strikes against Ukraine, citing newly declassified intelligence.