Ukrainian military helicopters carried out a targeted strike on an oil storage facility on Russian soil, the region’s governor claimed Friday.
"There was a fire at the petrol depot because of an air strike carried out by two Ukrainian army helicopters, who entered Russian territory at a low altitude," Vyacheslav Gladkov, governor of the Belgorod region that borders northeastern Ukraine, wrote in an early-morning Telegram post.
Ukrainian authorities have not confirmed the alleged attack.
The Kremlin said the reported Ukrainian airstrike will hinder future peace talks.
"Of course, this is not something that can be perceived as creating comfortable conditions for the continuation of negotiations," Kremlin spokesman Dmitry Peskov told reporters.
Eight tanks are now on fire at the depot in the city of Belgorod, the Emergency Situations Ministry told Interfax. Nearly 200 firefighters have been deployed to the scene.
Two oil depot employees received non-life-threatening injuries, Gladkov said. No deaths have been reported.
Rosneft, which owns the facility, told Russian news agencies it has evacuated its staff from the premises.
Belgorod Mayor Anton Ivanov said people whose homes are near the facility have been evacuated to the Belgorod Arena until the fire is extinguished.
"Two helicopters flew low over our houses. Then I heard explosions," local resident Elena Tishina wrote on the VKontakte social network on Friday.
"I distinctly heard the sound of rockets. After that there was an explosion at the tank farm. I lived in Novosadovo, so I heard and saw everything," resident Natalia Muravyova wrote in a VK post.
"I walked my dog this morning and saw a helicopter in the sky. A minute passed, and then I heard three bangs and saw black smoke," Dmitri Hmilevsky wrote.
On Wednesday, explosions could be heard from an arms depot in Belgorod but the authorities did not provide any explanation for the blasts.
Belgorod lies some 80 kilometers from the Ukrainian city of Kharkiv, which has fallen under heavy Russian bombardment since Moscow launched its war on Ukraine on Feb. 24.
AFP contributed reporting.