The residents of two villages in Russia's Belgorod region on Ukraine's northeastern border were evacuated after a fire at a munitions depot near the village of Timonovo.
The fire is the latest in a series of destructive incidents on Russian-occupied territory in Ukraine or inside Russia itself. Roughly 1,100 people reside in the villages of Timonovo and Soloti, around 15 miles (25 kilometres) from the Ukrainian border.
There were no casualties in the late Thursday blaze, the Belgorod region's governor Vyacheslav Gladkov said on Friday.
The fire came days after another ammunition depot exploded on Ukraine's Black Sea peninsula of Crimea, a Russian-occupied territory seized by Moscow in 2014.
Last week, nine Russian warplanes were reported destroyed at an airbase on Crimea, demonstrating both the Russians' vulnerability and the Ukrainians' capacity to strike deep behind enemy lines.
Ukrainian authorities have stopped short of publicly claiming responsibility.
But President Volodymyr Zelenskyy alluded to Ukrainian attacks behind enemy lines after the blasts in Crimea, which Russia has blamed on "sabotage". Russia's Deputy Foreign Minister Sergei Ryabkov said in televised remarks on Friday that statements from Ukrainian officials about striking facilities in Crimea mark "an escalation of the conflict openly encouraged by the United States and its NATO allies."
Ryabkov said Russian officials had warned the US against such actions in phone calls with high-level members of the Biden administration, adding that "deep and open US involvement" in the war in Ukraine "effectively puts the US on the brink of becoming a party to the conflict."
"We don't want an escalation, we would like to avoid a situation where the US becomes a party to the conflict, but so far we haven't seen their readiness to deeply and seriously consider those warnings," Ryabkov said.
Meanwhile, Kyiv and Moscow continued to accuse each other of shelling Europe's largest nuclear power plant, stoking international fears of a catastrophe on the
continent.
On Friday, Nikolai Patrushev, the secretary of Russia's Security Council, accused the US of encouraging Ukrainian attacks on the Zaporizhzhia nuclear power plant in southern Ukraine.
The facility has been controlled by Russian forces since shortly after the invasion began on February 24.
"In case of a technological disaster, its consequences will be felt in every corner of the world," Patrushev said. "Washington, London and their accomplices will bear full responsibility for that."
Ukraine has accused Russia of storing troops and weapons at the Zaporizhzhia plant and using its grounds to launch strikes against Ukrainian-controlled territory.
Ukrainian officials and military analysts say Moscow's forces have cynically employed the plant as a shield, knowing that the Ukrainians would be hesitant to fire back.
Russia has denied the accusations and, in turn, accused Ukrainian forces of repeatedly shelling the plant.
Following a visit to Ukraine on Thursday, Turkish President Recep Tayyip Erdogan said that Zelenskyy had asked him to ensure that Russia remove weapons stored at the plant as an "important step for world peace."
"Zelenskyy asked this of us especially: that Russia remove all mines and similar (weapons) there and for the issue to rapidly cease to be frightening. Because it is a threat," Erdogan said.