• Ukraine's spy chief said Russia helped North Korea fix a severe accuracy flaw in its KN-23 missiles.
• Often compared to the Iskandar-M, it's a ballistic missile with a range of over 400 miles.
• Budanov cited the KN-23 as an example of how Pyongyang is gaining from its fight against Ukraine.

North Korean KN-23 missiles had an accuracy flaw removed by Russian technicians as they were deployed against Ukraine, said Kyrylo Budanov, the head of Ukraine's intelligence agency.

Speaking to the South Korean media outlet Chosun Ilbo, Budanov cited the missile as an example of Pyongyang's combat tech receiving major improvements from the active fighting.

"Initially, its accuracy was severely flawed, with an error margin of 500 to 1,500 meters," he said in the interview, published on Monday. "But Russian missile experts made technical modifications, resolving the issue. The missile is now significantly more precise and a far greater threat."

The KN-23 is the missile's US designation, but North Korea has named it the Hwasong-11A. The solid-fueled ballistic missile is believed to have a range of about 430 miles and is often compared to Russia's Iskandar-M, with a typical payload of up to 1,100 pounds.

It's one of North Korea's newer weapons, debuting during a parade in 2018, with a range that would allow it to strike deep into South Korea. In July, Pyongyang said it tested an advanced version of the missile, the Hwasong-11Da-4.5, saying it can carry a 4.5-ton warhead.

The White House said in January 2024 that Russia had fired multiple North Korean short-range ballistic missiles against Ukraine, and it's widely believed that these were the KN-23 and KN-24.

Referencing the strikes, South Korea's ambassador to the United Nations said at the time that North Korea was using Ukraine as "a test site of its nuclear-capable missiles."

During his interview with Chosun Ilbo, Budanov said collaboration between Russia and North Korea was "reaching the highest levels," warning of a heightened threat to Pyongyang's enemies in Asia.

"North Korea is using this war to gain combat experience and modernize its military technology," he told the outlet. "This will have lasting consequences for the security landscape in the Asia-Pacific region."

North Korea's lessons from the war

The West and Seoul have been especially concerned by what they estimate is a deployment of 12,000 North Korean special forces in Kursk.

Western intelligence says about 4,000 of those soldiers have since been wounded or killed. However, Pyongyang's direct involvement has ignited fears that its surviving troops will pick up invaluable combat experience and knowledge of modern war.

Vadym Skibitskyi, the deputy chief of Ukraine's intelligence agency, told Chosun Ilbo that the North Korean troops are learning quickly.

"Their combat effectiveness has improved dramatically, not only with conventional weapons like tanks but also with advanced systems such as drones," Skibitskyi told the outlet.

Pyongyang's soldiers were initially reported to often charge headlong at Ukrainian positions in high-casualty assaults, indicating a force that's primed to aggressively follow orders in the face of death.

In the early days of North Korean troop encounters, Ukrainian sources also said that Pyongyang's troops didn't appear to know that drones could kill them.

But there are some clues that they're adapting.

In January, Ukraine's special forces released what it said were excerpts of a North Korean soldier's diary, one of which described a tactic of sending a soldier into the open to bait drones that could then be gunned down by comrades.

In exchange for his troops and weapons, North Korean leader Kim Jong Un is believed to be receiving technical assistance from Russia for his space and arms programs, as well as cash, raw materials, and food.

Their collaboration underscores a budding relationship between Pyongyang and Moscow, as both seek to lean on each other to help weather international sanctions imposed on their economies.

• Russia is experiencing repeated struggles with its new intercontinental ballistic missile.
• Russia used to use Ukrainian expertise to work on that type of missile.
• But Russia's attack on Ukraine in 2014 and its 2022 invasion isolated it from that expertise.

Russia's intercontinental ballistic missile program is in trouble, facing persistent struggles with its new Sarmat missile. And it doesn't help that the country has cut off expertise it once depended on by waging war on its neighbor.

"Historically, a lot of the ICBM manufacturing plants and personnel were based in Ukraine," Timothy Wright, a missile expert at the International Institute for Strategic Studies, told Business Insider.

Ukrainian expertise

Ukraine became independent when the Soviet Union collapsed in 1991, but its defense industry continued to be intertwined with Russia's. Ukraine has expertise in nuclear and missile technology, as well as manufacturing knowledge.

Russia had been decreasing its reliance but hadn't yet severed critical ties when it attacked Ukraine in 2014, leaving it with gaps that could affect development projects.

Since the dissolution of the Soviet Union, Russia has developed capable solid-fueled ICBMs. But with Sarmat, it decided to use a liquid-fueled system.

The problem with that "is that the Russians haven't done this in about 30-plus years," Wright said. "They haven't got any recent experience doing this sort of stuff with land-based ICBMs."

Fabian Hoffmann, a missile expert at the Oslo Nuclear Project, told BI that it was "a bit of a question of 'Have they retained the expertise?' because all the people who built their previous missile have retired or are dead."

"Some of them are in Ukraine, which had a big part in the Russian ICBM program," he said. "So that's a major issue."

Wright described Russia's choice to use liquid-fuel technology as "a really weird choice that they made" because it was "something the Ukrainians previously did for them." He said that was "one of the reasons why they're having lots of problems."

The Sarmat is designed to replace the Soviet-era R-36, which NATO calls the SS-18 "Satan." Its earliest version first entered service in the 1970s and has been modified since.

The company that designed and maintained it, Pivdenmash, known as Yuzhmash in Russia, was in what is now modern-day Ukraine. (Russia appeared to target the Pivdenmash plant in an attack with a new missile type in November.)

Ukraine cut ties

Russia wanted to develop more of this kind of expertise and capability itself. "After the dissolution of the Soviet Union, Russia found itself in a position where essentially it was having to rely on external countries to maintain its existing forces and also then contribute to the development of other ones," Wright said.

But doing so was a challenge that took time. "So they continued working with Ukrainians up until 2014," he said.

In March 2014, Russia annexed Ukraine's Crimea region, claiming it as part of Russia despite international outcry, and ignited conflict in Ukraine's east that continued until Russia launched its full-scale invasion of Ukraine in February 2022.

In response to Russia's actions in Crimea, "the Ukrainians pretty much terminated all contracts around the maintenance of ICBMs at that point — so that's where the big cutoff happens," Wright said.

The collapse in cooperation between Ukraine and Russia "accelerated" Russia's efforts to replace the R-36 so it wouldn't rely on Ukraine as much, Maxim Starchak, an expert on Russian nuclear policy and weaponry, wrote in a 2023 analysis.

"All cooperation with Ukrainian contractors ceased," and the responsibility for maintaining the R-36s went to Russia's Makeyev Rocket Design Bureau, Starchak said, adding: "But this was a stopgap solution. Launches ceased, with missiles and warheads simply undergoing annual checks."

Ukraine banned military cooperation with Russia and stopped supplying Russia with any military components in June 2014. That left Russia without much of the expertise it wanted for Sarmat.

Neither of the two strategic-missile developers in Russia — the Makeyev Rocket Design Bureau nor the Moscow Institute of Thermal Technology — have recent experience developing a liquid-fueled ICBM, Wright said.

Ukraine also made other ICBM components, such as guidance systems and security protocols to prevent the unauthorized detonation of a nuclear device.

Russian military experts had predicted that Ukraine pulling its cooperation with Russia would completely collapse Ukraine's defense industry. And while it did suffer, that industry is now thriving, with homegrown defense companies and major Western manufacturers all working in the country in response to Russia's invasion.

Russia still has many missiles that are hitting Ukraine and pose a big threat to Europe, and it has recently ramped up its missile production. But Russia's aggressive actions in Ukraine appear to have continued to harm its missile program. Roscosmos, a Russian space agency that also makes missiles, said last year that canceled international contracts had cost it almost $2.1 billion.

Many countries have put sanctions on Russia in response to the invasion, and the sustained military effort is also hammering Russia's economy. Hoffmann described Russia as having "really restricted monetary means" to fix its missile problems.

Sarmat's problems

Russia's RS-28 Sarmat ICBM seemed to have suffered a catastrophic failure during a September test, appearing to have blown up. Satellite pictures showed a massive crater around the launchpad at the Plesetsk Cosmodrome, a spaceport in northwestern Russia.

That apparent failure followed what missile experts said were multiple other problems. The powerful missile's ejection tests and its flight testing have both been repeatedly delayed, and it previously had at least two canceled flight tests and at least one other flight test failure, according to the Royal United Services Institute think tank in London.

Russia has poured a lot of money and propaganda into the Sarmat missiles. President Vladimir Putin in 2018 bragged that "missile defense systems are useless against them, absolutely pointless" and that "no other country has developed anything like this."

But it doesn't work right. With the setbacks facing the Sarmat and no other replacement, the R-36 keeps having its life extended. Wright said the missile was "already really, really past its service life." And sooner or later, things are going to fall apart.

Hoffmann said Sarmat's struggle "obviously is proof of the fact that whatever expertise there is in Russia right now, it's not enough to complete this program in a satisfactory way."