Russia is using repurposed S-400 training missiles to stretch Ukraine’s Patriot defenses

Russia has turned a missile originally built for air-defense training into one of the most common ballistic threats facing Ukraine.

Ukrainian strike data reviewed by Reuters shows that RM-48U missiles made up more than half of 228 confirmed Russian ballistic and hypersonic strikes in July and the first eight days of August. In July alone, 87 of 158 such strikes were attributed to RM-48Us. In the first eight days of August, they accounted for 36 of 70.

That matters because the RM-48U does not need to be as accurate or sophisticated as an Iskander to create a serious problem for Ukraine. It only needs to arrive fast enough, carry a dangerous warhead and force Ukrainian air-defense crews to treat it as a real ballistic threat.

Ukraine’s Defense Intelligence says Russia is rebuilding decommissioned surface-to-air missiles and target missiles associated with the S-400 system and converting them into ground-strike weapons.

According to the agency, the RM-48U combines components from several missile families used with the S-300 and S-400 systems. It uses a solid-fuel motor from the 48N6DM, a tail section from the 48N6E2 and elements from the 9M96 and 48N6E2 in its instrument section.

Defense Intelligence says the missile follows a ballistic trajectory, can reach targets up to about 400 kilometers away and carries a 199-kilogram high-explosive fragmentation warhead. Its guidance combines inertial navigation with satellite navigation.

The result is not a replacement for Russia’s more capable Iskander ballistic missile. Ukrainian prosecutors told Reuters the RM-48U is less accurate and less powerful. But that is part of the point.

The RM-48U gives Russia another way to increase the number of fast ballistic targets in an attack without spending the same number of its better strike missiles.

Reuters reported that the surge in RM-48U launches coincided with a sharp fall in Iskander use. Russia fired more than 100 Iskanders in June, according to the Ukrainian data reviewed by Reuters, but only 38 in July as RM-48U use increased.

Sidharth Kaushal of the Royal United Services Institute told Reuters that the missiles allow Russia to conserve more capable systems, including Iskanders, KN-23s and Zircons, for periods when Moscow may want to intensify its ballistic campaign.

Ukraine’s Defense Intelligence says Russia also plans to increase RM-48U production sharply, from more than 200 missiles last year to around 480 in 2026.

This turns what might have looked like an improvised use of old equipment into something closer to a repeatable production and inventory strategy.

Ballistic missiles are among the hardest targets in Ukraine’s air-defense problem.

Reuters reported that Ukraine was critically short of U.S.-made Patriot interceptors, which are central to its ability to engage Russian ballistic missiles. That creates an unfavorable exchange for Kyiv: even a less precise Russian missile can force Ukraine to consider using a scarce high-end interceptor if the incoming trajectory threatens a city, power facility, railway or other critical target.

The RM-48U therefore adds pressure in two ways. It increases the number of ballistic objects Ukraine must track and evaluate, while helping Russia preserve more capable missiles for targets where accuracy matters more.

The tactic also complicates the assumption that an older or repurposed weapon is automatically a marginal threat.

Ukrainian prosecutors linked an RM-48U to the August 5 strike on the Kvitnevyi railway station in the Brovary district near Kyiv, where eight people were killed. Investigators said forensic evidence from the crater, fragments and damage pattern supported that conclusion. They also told Reuters that RM-48Us deviated from their intended targets by about 300 meters on average.

Reuters said it could not independently verify those Ukrainian forensic findings.

Russia’s Defense Ministry did not respond to Reuters questions about its use of RM-48Us. Moscow has repeatedly denied deliberately targeting civilians and said that its August 5 strike in the Brovary area hit a logistics center used to store drone components.

The important development is not simply that Russia has another missile type.

It is the scale.

A weapon built from older air-defense and target-missile components has become a major share of Russia’s confirmed ballistic strike volume. That gives Moscow a way to keep pressure on Ukrainian cities and infrastructure while managing the stocks of its more sophisticated weapons.

For Ukraine, the answer cannot be only to shoot down more missiles with the same limited pool of expensive interceptors. It also increases the urgency of expanding interceptor production, adding more anti-ballistic capacity and improving the ability to discriminate among incoming threats quickly enough to use scarce defenses efficiently.

The RM-48U is dangerous precisely because it does not have to be Russia’s best missile. At scale, it only has to be dangerous enough that Ukraine cannot afford to ignore it.

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