Russia is believed to have used some 60 ballistic missiles provided by North Korea in the war against Ukraine, a Ukrainian media outlet has reported, citing its intelligence authorities.

Andrii Chernyak, the representative of the Defense Intelligence of Ukraine's defense ministry, shared the analysis in an interview with Radio Svoboda, according to a report by local media outlet RBC on Monday.

Chernyak confirmed that the Russian army had launched about 60 KN-23 ballistic missiles at Ukraine, the report said.

A DIU spokesperson said that the KN-23 missiles used by the Russian forces were based on "outdated technologies" that affect their accuracy, adding that Russia is receiving a "vast amount" of artillery ammunition from the North.

The report came after the Ukrainian authorities claimed last month that the North had provided some 100 short-range ballistic missiles, such as KN-23s and KN-24s.

The KN-23 and KN-24 each refer to the North Korean-made tactical guided weapons similar to Russia's Iskander-M and the US' Army Tactical Missile System, respectively, known as the Hwasong-11 types in North Korea.

North Korea is suspected of having provided weapons and munitions to Moscow to assist Russia's war in Ukraine.

At the summit in Pyongyang in June, North Korean leader Kim Jong-un and Russian President Vladimir Putin signed a major defense pact that includes a mutual defense clause.

South Korea and the United States have accused North Korea of sending thousands of soldiers to Russia, with some of them engaging in combat in Russia's western Kursk border region.

On Monday, Matthew Miller, the US State Department spokesperson, reiterated that the North Korean troops in combat against Ukrainian forces are "legitimate targets," in an interview with a Japanese media outlet.

Ukrainian President Volodymyr Zelenskyy has said that some of the North Korean soldiers have been killed or injured during combat. (Yonhap)