North Korea claims to have tested a new solid-fuel hypersonic missile as it continues to try and develop more powerful and harder-to-detect weapons.
The launch came two months after the country claimed to have successfully tested engines for the new type of missile.
State-run media in the dictatorship said Sunday's launch was aimed at verifying the reliability of the weapon, suggesting it is an upgrade to the regime’s previous technology.
North Korean officials often make unsubstantiated claims about their weaponry.
On Saturday, the South Korean and Japanese militaries detected a launch from a site near the North Korean capital of Pyongyang, in what was the North's first ballistic test of 2024.
South Korea's Joint Chiefs of Staff said Sunday’s missile flew about 620 miles before landing in the waters between the Korean Peninsula and Japan.
The North's existing intermediate-range ballistic missiles or IRBMs are powered by liquid-fuel engines, which are fueled up before launch and cannot stay fuelled for long.
Missiles with built-in solid propellants can be made ready to launch faster and are easier to move and conceal.
It comes as North Korea's foreign minister visits Russia for three days of talks, as international concern grows over an alleged arms cooperation deal between the two countries.
A delegation led by foreign minister Choe Son Hui arrived in Moscow on Sunday, according to North Korea's official Korean Central News Agency.
She is to meet her Russian counterpart, Sergey Lavrov, on Tuesday, Russian foreign ministry spokesperson Maria Zakharova said.
Ms Choe is visiting at Mr Lavrov's invitation, the ministry said.
The United States and South Korea say North Korea has provided Russia with arms, including artillery and missiles, to help its fight in Ukraine.
The Biden administration said it has evidence that missiles provided by North Korea to Russia have been used in Ukraine.
In a joint statement last week, the US, South Korea and their partners said the missiles support Russia's war, while North Korea receives valuable technical and military insights in return.
Koo Byoungsam, spokesperson for South Korea's Unification Ministry, said it is closely watching Ms Choe's visit to Russia.
He accused North Korea and Russia of "maintaining illegal cooperation activities, including arms exchanges" followinga visit by Kim Jong Un to Russia in September in which he met with Vladimir Putin.
Both Russia and North Korea have denied accusations of North Korean arms transfers to Russia.
