The test launches, which took place on both Saturday and Sunday, were observed by high-level officials, KCNA said, adding that the tests had been carried out "successfully".

The missiles travelled for 7,580 seconds along "oval and pattern-8 flight orbits" above North Korea and its territorial waters, and hit targets 1,500 kilometres (about 930 miles) away, KCNA said.

The report called the missile a "strategic weapon of great significance", adding that "in all, the efficiency and practicality of the weapon system operation was confirmed to be excellent".

It also said the development of the missile system held "strategic significance", giving North Korea "another effective deterrence means" for protecting the state and aiding in "strongly containing the military maneuvers of the hostile forces".

The Pentagon did not immediately reply to a request for comment about the reported test launches.

Pyongyang is under a range of international sanctions over its nuclear weapons and ballistic missile programmes, which it continues to pursue.

Nuclear talks with the United States have been stalled since the collapse of a 2019 summit in Hanoi between North Korean leader Kim Jong Un and then-president Donald Trump over sanctions relief -- and what Pyongyang would be willing to give up in return.

Biden's North Korea envoy Sung Kim has repeatedly expressed his willingness to meet his Pyongyang counterparts "anywhere, at any time".

But the impoverished North has never shown any indication it would be willing to surrender its nuclear arsenal, and has rebuffed South Korean efforts to revive dialogue.

Last month, the UN atomic agency (IAEA) said Pyongyang appeared to have started its plutonium-producing reprocessing reactor at Yongbyon, calling it a "deeply troubling" development, and Kim's sister and key adviser Kim Yo Jong demanded the withdrawal of US troops from the peninsula.

Last week, South Korea tested a homegrown submarine-launched ballistic missile -- a technology the North has long sought to develop.

The North showed off four such devices at a military parade overseen by Kim in January, with KCNA calling them "the world's most powerful weapon".

But while North Korea has released pictures of underwater launches, most recently in 2019, analysts believe that was from a fixed platform or submersible barge, rather than a submarine.