Security Council on Dec. 18.Leff said that the researchers from his group examined remnants of four North Korean missiles recovered in Ukraine in July and August. One of them had marks showing it was procured in 2024, according to the researcher."This is the first public evidence of missiles having been produced in North Korea and then used in Ukraine within a matter of months, not years," Leff said.North Korea has shaped up to be Russia's leading supporter in its full-scale war against Ukraine, providing not only ballistic missiles and artillery ammunition but also soldiers.Leff told the U.N. Security Council back in June that his group has "irrefutably" established that Russia is using North Korean missiles against Ukraine.According to Ukraine's military intelligence, Russian forces have launched at least 60 North Korean ballistic missiles, namely the short-range KN-23/24 model, as of early December.