By Niamh Kennedy, Maria Kostenko and Victoria Butenko, CNN

(CNN) — A Ukrainian drone attack launched overnight destroyed an ammunition depot in the western Russian region of Tver, a source from Ukraine’s Security Service (SBU) told CNN on Wednesday, causing a massive blast.

The Ukrainian drones targeted the Russian defense ministry-operated warehouse in the city of Toropets, which was storing Iskander tactical missile systems, Tochka-U tactical missile systems, guided aerial bombs and artillery ammunition, the source said.

Large fires broke out from the debris of drones repelled by local air defenses, the regional government said, prompting the governor, Igor Rudenya, to order a partial evacuation of the area during the early hours of Wednesday.

Earthquake monitors now believe explosions from the drone attack may have generated seismic activity. Ben Dando, a seismologist at the Norwegian seismology research foundation NORSAR, told CNN that its sensors “detected seismic signals, of magnitude 2.5 to 2.8, in northwest Russia which look to be associated with the drone attack launched by Ukraine.”

NORSAR, which has been using seismic monitors since 2022 to evaluate the impact of the war in Ukraine, is currently analyzing the preliminary data to capture the full extent of the blast, Dando added.

Satellite images taken by Maxar Technologies on Wednesday morning showed huge plumes of smoke rising up from several depot buildings, as well as extensive damage to the buildings and nearby forest.

Fires continue to burn, as seen in the Maxar Technologies images.

Russian state news agency TASS reported that a drone attack had been launched on the city of Toropets overnight causing a fire “due to the fall of debris,” without specifically mentioning any targeting of a weapons facility.

Videos circulating on social media, verified by CNN, showed loud detonations and multiple buildings in the depot complex on fire.

Affected residents, including 11 children, have already been evacuated to the settlements of Kunya and Velikiye Luki in the neighbouring Pskov region, TASS said. No civilians are thought to have been injured in the drone attack, the news agency reported, citing Rudenya.

“Now we are engaged in evacuating the population, residents, maintaining public order,” Rudenya said in a later video statement, stressing that multiple emergency service units were involved in the response.

Rudenya made the call to evacuate so emergency services at the scene could work fully to bring the blazes under control, the local government said in a post on its official Telegram channel.

The Ukrainian security source told CNN that attacks of this nature are being used “methodically” to reduce Russia’s missile potential, adding that plans for further attacks on “similar” Russian military facilities are “proceeding.”

Toropets is located around 300 miles from the Ukrainian border and about 250 miles west of Moscow.

Ukraine has been pushing its key allies, including the United States, to give the go-ahead to carry out missile strikes on targets deeper into Russian territory. Last week, Russian President Vladimir Putin warned NATO members that lifting restrictions on Ukraine’s use of long-range missile systems would mean entering into war with Russia itself.

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CNN’s Anna Chernova contributed to this report