Drones struck Russia's Ryazan and Voronezh oblasts overnight on May 1, causing a fire to break out at a Ryazan oil refinery, the oblasts' governors reported.
According to the Russian Telegram news channel Astra, an oil refinery in Ryazan Oblast was hit by drones during the night, causing a fire at the facility. Ryazan Oblast Governor Pavlo Malkov said an "inspection is ongoing" at the site.
Voronezh Oblast Governor Aleksandr Gusev reported that Russian air defense units shot down a drone over the suburbs of Voronezh.
"As a result of falling debris, the glass in the building under construction was broken," Gusev said.
No casualties have been reported in either attack.
Previous attacks and fires at the oil refinery in Ryazan Oblast were reported in March and April, as Ukrainian forces launched a series of successful drone strikes targeting Russia's fuel industry.