Pyongyang, North Korea - North Korea fired multiple types of short-range ballistic missiles Thursday, South Korea's military said, around a week after leader Kim Jong-un tested a new weapons system for his latest warship.

Seoul's military said it had "detected the launch of various types of short-range ballistic missiles" towards the Sea of Japan in the morning, the Joint Chiefs of Staff said.

The missiles flew up to about 500 miles before splashing down in waters to the east of the peninsula, the JCS said, adding it strongly condemned the North for a "clear act of provocation that poses a serious threat to peace and stability".

"Our military, under the strong South Korea-US combined defense posture, is closely monitoring various North Korean activities to prevent any misjudgment (by the North)," it said in a statement.

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The launch, the nuclear-armed North's first missile test since March, came about a week after Kim oversaw the test-firing of a new warship weapons system.

Pyongyang unveiled the 5,000-ton destroyer-class vessel named Choe Hyon last month.

North Korea claims the vessel was equipped with the "most powerful weapons," and that it would "enter into operation early next year."

Some analysts have said the ship could be equipped with short-range tactical nuclear missiles – although North Korea has not proven it has the ability to miniaturize its nukes.

The South Korean military has said the destroyer could have been developed with Russian help, possibly in exchange for Pyongyang deploying thousands of troops to help Moscow fight Kyiv.

Russia and North Korea also recently announced that they had started building the first road bridge linking the two neighbors.