In an operation that showcased the destructive potential of low-cost, first-person-view (FPV) drones, Ukrainian troops have destroyed two bridges inside Russia’s Belgorod region near the border with Ukraine’s Kharkiv region. The attacks, which targeted supplies of Russian mines and ammunition stashed under the bridges, were carried out by the 58th Separate Motorized Infantry Brigade.

The 58th Brigade said it decided to strike the bridges after becoming suspicious of activity around one of them. “It became clear that something was going on there,” a representative of the unit said. As the brigade could not use a standard reconnaissance drone under the bridge without losing signal, it instead sent an FPV drone equipped with fiber optics optics to inspect the area.

“The [FPV] drone flew right to the middle of the bridge, which is a very hard-to-reach place for our intelligence-gathering. We saw the mines, and we struck,” the brigade representative said. A video released by the brigade shows the drone approaching the bridge, scanning for the hidden munitions, and then detonating in an explosion.

A second camera placed on a nearby building captured the blast from afar. CNN was able to geolocate the bridge to Russia’s Belgorod region, near the border with Kharkiv. After its initial success, the unit checked another bridge in the same area and found it was also mined. It again launched a drone to trigger another powerful explosion. “We saw an opportunity and took it,” the brigade said.

The entire operation is remarkable not only for the distance at which the Ukrainian troops were able to strike, but also for the low cost. The drones used in the attacks cost between 25,000 and 30,000 Ukrainian hryvnias, or about $600–$725, each.

In normal circumstances, Ukraine would have to use expensive guided missiles or precision bombs to attack a bridge 25 kilometers inside Russia. For instance, in the past, Ukraine has resorted to U.S.-supplied HIMARS systems to hit bridges in Russia’s Kursk region. The HIMARS launchers themselves cost millions of dollars, and individual rockets are tens of thousands of dollars apiece. In Belgorod, Ukraine achieved the same effect using drones worth less than a high-end smartphone.

Cost aside, the operation also demonstrated how Ukrainian forces have adopted relatively cheap drones to great effect. In June, Ukrainian drones were smuggled near Russian military airfields and used to damage or destroy dozens of aircraft. “We’ve seen drone operations against Russian airfields several times,” said military analyst Mykola Bielieskov. “That was just another example of how even a not-very-powerful weapon can achieve very important effects.”

Ukraine destroyed two bridges in Russia’s Belgorod region near the border with the Kharkiv region.

The timing of the bridge attacks could not be worse for Ukrainian forces. For the past several weeks, Russia’s army has been making slow but steady progress in eastern Ukraine. At the same time, Moscow has been waging a campaign of near-daily missile and drone strikes on Ukrainian cities.

After a summer lull, Russian attacks have also increased in number and lethality. In his September 21 address to the nation, President Vladimir Putin also dashed Ukrainian hopes for any ceasefire, saying he would not order a pause in the offensive. Against this backdrop, the Ukrainian strike on the bridges gave Kyiv a badly needed victory. Russia has not yet acknowledged the loss of the bridges. However, their destruction will complicate its logistics in the Belgorod region and disrupt supply lines to Russian troops deployed along the border with Ukraine.

FPV drones have become one of Ukraine’s most cost-effective weapons in the current conflict.

For the military, the Belgorod strikes served as another reminder of what they have known for months now: innovation is the name of the game. With Western supplies often scarce and Russian forces often numbering them, Ukraine has had to improvise to keep the fight going. FPV drones, often built from commercial parts and modified by volunteers, have become one of Kyiv’s most effective tools. “The value of these drones cannot be overstated,” the 58th Brigade representative said. “They allow us to achieve results that would otherwise require weapons that we don’t have.”

As long as the war in Ukraine rages on, Kyiv’s ability to adapt and innovate will be critical in the face of battlefield disadvantages. And for now, two destroyed bridges in Belgorod are a stark testament to the strategic impact that even a low-cost drone can have.