Vladimir Putin has declared a state of emergency in the Voronezh region of Russia after Ukraine forces struck an ammunition warehouse overnight.
Ukraine's military intelligence directorate claimed to have blown up a warehouse storing 5,000 tonnes of ammunition in the region's Ostrogozhsky district, AP has reported.
Regional governor Aleksandr Gusev said that two people were injured in the blast on Friday night and that 200 were evacuated.
There has been some discrepancy over how the ignition came about, with some claiming it was the result of falling ammunition while others said it was a direct target.
A state of emergency has since been declared by Russian officials.
The news came as Russia and Ukraine exchanged more than 100 prisoners of war on Saturday for what was the third Ukrainian independence day since the war began in February 2022.
Ukraine said the 115 servicemen who were freed were conscripts, many of whom were taken prisoner in the first months of Russia's invasion.
Among them are nearly 50 soldiers captured by Russian forces from the Azovstal steelworks in Mariupol.
The Russian defence ministry said the 115 Russian soldiers had been captured in the Kursk region, where Ukrainian forces launched their surprise offensive into Russia two weeks ago.
The ministry said the soldiers were currently in Belarus, but would be taken to Russia for medical treatment and rehabilitation.
Ukrainian president Volodymyr Zelensky said in a tweet that the United Arab Emirates had again brokered the exchange, the 55th since Russia launched a full-scale invasion of its neighbour in February 2022.
Photos attached to Mr Zelensky's post show gaunt servicemen with shaven heads and wrapped in Ukrainian flags.
"We remember each and every one. We are searching and doing our best to get everyone back," Mr Zelensky said in the post.
