It comes amid renewed waves of missile attacks by Russian forces against Ukraine, particularly the capital Kyiv, where many have taken refuge in the underground system.
According to accounts, explosions were reported at two Russian air bases, including one that houses bombers carrying nuclear weapons.
RIA Novosti reported on Monday that three new members were killed and six others were injured when a fuel tanker detonated at a Ryazan air base.
The explosion at the station, which houses long-range flight tankers that refuel bombers in the air, also damaged one aircraft.
Authorities in the Volga River region of Saratov said they were also examining claims of an explosion near the Engels air base.
Strategic bombers Tu-95 and Tu-160, capable of carrying nuclear weapons, have been used to launch strikes against Ukraine from this base.
Regional media cited residents who reported seeing a flare of light emanating from the area.
Roman Busargin, the regional governor of Saratov, stated that there was no damage to civilian infrastructure, although investigations into any mishaps at military stations continue.
When asked whether Vladimir Putin has been updated on the incident at the Engels base, Kremlin spokesperson Dmitry Peskov stated that the Russian leader is routinely kept abreast of current events.
Air Vice-Marshal Retired Sean Bell stated that the causes of the explosions are unknown, although it appears doubtful that they were caused by Ukrainian long-range weaponry.
“It may have been an accident or an act of sabotage,” he explained.
On Monday, Russia launched a new wave of missile attacks against Ukraine.
According to officials, two persons were slain in Zaporizhia. Also hurt were three people, including a youngster.
People sought refuge in the underground metro of Kyiv as new strikes swept the capital city.
As the temperature dropped to -5C, men, women, and children donned caps and heavy coats to stay warm (23F).
Meanwhile, the office of Ukrainian president Volodymyr Zelenskyy reported that three rocket attacks had targeted his hometown of Kryvyi Rih, hurting three persons and killing one.
In the Kharkiv region, one person was killed when S-300 missiles targeted civilian facilities in the city of Kupyansk, according to the report.
It occurred as Western nations began imposing a $60-per-barrel price ceiling and a ban on some types of Russian oil.
The move was part of a new set of steps designed to increase pressure on Moscow about the war.
Russia, the second-largest oil producer in the world, relies on the sale of oil and gas to support its economy, which has already been subjected to extensive international sanctions due to the conflict in Ukraine.
