International- The US said this week that Russia started using missiles it got from North Korea to attack Ukraine.
- The ISW experts noted that it's focus is on upping the quantity of ballistic missiles it can get.
Russia is likely looking for missiles from North Korea and Iran because they are a type that Ukraine struggles to intercept, according to military experts.
Analysts at the Institute for the Study of War noted in an update on Thursday that Russia's efforts to get missiles from its allies focused on ballistic missiles.
That type, as opposed to cruise missiles, "appear to be more effective at penetrating or avoiding Ukrainian air defenses," the ISW said.
Ballistic missiles fly on a fixed trajectory, and tend to be faster than cruise missiles, which are more maneuverable but slower.
The ISW compared Ukraine's air defenses' interception rate of Russian cruise missiles vs ballistic missiles since December 29, based on numbers shared by Ukrainian officials and reports.
While Ukraine said it intercepted 149 of the 166 cruise missiles Russia fired — about 90% — it said Ukraine only stopped a "handful" of ballistic missiles.
It highlighted that Russia had found success with converting its anti-air missiles into weapons of attack: Ukraine struggles to block rounds fires from repurposed S-300 and S-400 systems, the ISW said.
Ukraine isn't incapable of stopping ballistic missiles, the ISW said, noting some successes.
On December 30, it shot down an Iskander-M missile during a less intense series of Russian missile and drone strikes, Valerii Zaluzhnyi, the commander-in-chief of Ukraine's Armed Forces, said at the time.
Ukrainian forces also intercepted all Iskander-M and S-300/S-400 missiles fired at Kyiv by Russian forces on December 12, the Kyiv City Military Administration reported at the time.
And the Ukrainian military used Western-supplied Patriot systems to intercept all 10 Kinzhal missiles fired by Russian forces in Ukraine on January 2, the Air Force of the Armed Forces of Ukraine reported.
The ISW concluded that Russia's success with ballistic missiles depends on how intense an attack they are part of.
The report came after as National Security Council spokesman John Kirby said on Thursday that Russia had acquired "several dozen" ballistic missiles from North Korea and used them on Ukraine.
Citing US officials, The Wall Street Journal reported on Thursday that Russia was also in talks with Iran to buy short-range ballistic missiles with a view to better targeting Ukraine's infrastructure.