Ukraine’s 58th Separate Motorized Infantry Brigade destroyed two bridges deep inside Russia this week, striking munitions supplies intended for use by Russian forces fighting in the Kharkiv region.

The bridges, located in Russia’s Belgorod region near the border with Ukraine, were used by Russia to store ammunition, according to the Ukrainian military. Both bridges were mined by Russia to prepare for their demolition. The 58th Brigade launched an FPV drone to inspect under one of the bridges, discovering “tens of anti-tank mines” and other munitions.

Following the discovery, the brigade launched an FPV drone packed with fiber optics under the bridge to destroy the hidden munitions. In a video of the attack, published by the brigade on Telegram, the drone detonates in a massive explosion.

CNN geolocated the attack to Belgorod, from where the drone was launched to strike the bridge near the border with Kharkiv. The operation was repeated on another bridge mined by Russian forces. “Seeing an opportunity we took it,” the brigade tweeted.

CNN was unable to independently verify the authenticity of the video or images of the bridges. CNN also contacted Russia’s military and Ministry of Defense about the bridge strikes but did not immediately receive a response.

“The drones are equipped with fiber optics and are remotely controlled. We did not lose them and received information,” the brigade told CNN.

FPV drones, which resemble toys and can be bought off the shelf, have become a key weapon in the Ukraine conflict as Russia battles with logistics and supply shortages in Ukraine.

In late May, Russia claimed to have struck a “BRDM reconnaissance vehicle” of Ukraine’s 58th Brigade with a Kinzhal air-launched missile. Video of the strike appears to show an FPV drone flying along a Russian road being struck by an explosion. Russia launched a total of eight drones at the brigade and destroyed two vehicles in the same area in the following days.

Video posted on social media this month showed what appeared to be an FPV drone strike in a Kharkiv district. Ukraine’s Air Forces command said the drones were being “used in the interests of the Russian Armed Forces.”

In June, the Ukrainian Armed Forces released a statement saying Russia had used explosive drones to target Ukraine, and that it would “continue to make enemy drones self-destruct.”

Ukrainian and Russian forces have also used drones to target each other’s facilities. In June, a Russian T-72B tank used a drone to scout a road in Kharkiv and Ukrainian shelling destroyed a Russian military drone on a road in Krasnodon.

An explosive drone struck a Ukrainian school in Kharkiv in May, with at least one person killed in the attack, while a Ukrainian drone attack destroyed a Russian military facility in September.

A Russian commander has also been accused of providing Russia with a drone that damaged a Ukrainian transport aircraft. The commander, Alexei Morozov, was found to have given Russia military drones in August and September.

CNN also spoke to a source familiar with the operations who said it was possible that a Russian-made drone had been used, although it was unclear if it was the same one as used in the Kharkiv incident.

CNN also contacted the Russian military about the Kharkiv incident but did not immediately receive a response.