It shared footage, which Express.co.uk has not been able to verify, appearing to show an explosion and flash of light in the night sky.
The clip was captioned: “Residents of Voronezh, Russia, report a loud explosion on the outskirts of the city”.
Igor Sushko, who describes himself as a Ukrainian American in his Twitter bio, wrote on the platform: “Voronezh in Russia is under attack!
“Doubtful this has anything to do with Ukraine. Appears to be internal Russian developments. The Voronezh-45 nuclear military facility captured by Wagner PMC during the coup is in the area.”
Further videos shared by Live: Ukraine, showing the date July 13 and time 10.55pm, show a ball of light rise into the night sky.
Voronezh is about 180 miles (290km) from Russia’s northeastern border with Ukraine.
Twitter account Spriter Team, which describes itself as independent and activist, also shared footage, writing on the platform: “Explosion in the sky near Voronezh.
“Apparently, air defence forces shot down an enemy object in the village of Maslovsky. A roar and flash in the sky caught the cameras. There are no official data yet”.
It emerged earlier this week that a contingent of Wagner mercenaries drove to an army base storing nuclear weapons near Voronezh, having diverted from a main column heading towards Moscow during the failed coup attempt in June.
Ukraine’s head of military intelligence, Kyrylo Budanov, told Reuters that Wagner fighters reached the nuclear base and that their aim was to acquire small, Soviet-era nuclear devices in order to “raise the stakes” in their mutiny.
There is no suggestion the reported explosions are linked to Wagner.
Matt Korda, a Senior Research Associate and Project Manager for the Nuclear Information Project at the Federation of American Scientists, told the agency it would be “virtually impossible for a non-state actor” to breach Russian nuclear security.
The Voronezh region is reportedly also home to a prison colony which houses 119 people opposed to Russia’s so-called “special military operation” in Ukraine.
Vladimir Osechkin, an exiled Russian human rights activist who founded Gulagu.net to document abuses, showed news wire AP a Russian prison document from 2022 saying 119 people “opposed to the special military operation” in Ukraine were moved by plane to the main prison colony in the Voronezh region.