North Korea launched several short-range ballistic missiles towards the sea off its eastern coast, according to Reuters.
The Joint Chiefs of Staff of South Korea reported that the missiles were fired from the city of Wonsan on the eastern coast, while Japan's NHK television reported that the short-range missile had already fallen.
In recent months, North Korea has conducted launches of ballistic and cruise missiles, as well as tactical missiles, branding them as part of its military modernization program.
Earlier on Friday, the influential sister of North Korean dictator Kim Yo Jong said that the tactical weapons were solely for deterring South Korea, once again denying Pyongyang's export of such armaments.
US and South Korean officials have accused the North of supplying weapons to Russia to assist Moscow in replenishing its supplies for use in the war against Ukraine. Both Moscow and Pyongyang have dismissed the allegations.
The missile launches coincided with Russian President Vladimir Putin's visit to the Chinese city of Harbin in northeastern China.
Putin and Chinese President Xi Jinping criticized Washington and its allies for what they termed as "intimidation in the military sphere" against North Korea during their meeting in Beijing.
Weapons supplies from DPRK to Russia
Despite international sanctions prohibiting Pyongyang from exporting its weapons, satellite imagery released by research groups and the US government depict a flow of arms from North Korea to Russia, and then to ammunition depots near the Ukrainian border.
On May 16, the US announced new sanctions on arms trade facilitating Moscow's war against Ukraine. The US Treasury Department stated that Russia had deployed over 40 ballistic missiles and other munitions in the conflict, in violation of UN Security Council resolutions.