Ukraine on Friday claimed it downed a Russian strategic bomber, which Moscow officials said the plane crashed in a sparsely populated area due to a malfunction after a combat mission.
Neither claim could be independently verified.
Previous Ukrainian claims of shooting down Russian warplanes in the Russia-Ukraine war have met with silence or denials from Moscow.
The Ukrainian report said the air force and military intelligence cooperated to bring down with anti-aircraft missiles the Tu-22M3 bomber, which Russia commonly uses to fire Kh-22 cruise missiles at Ukrainian targets from inside its own airspace, according to an Associated Press report.
The plane is also equipped to carry nuclear warheads.
The Russian defense ministry, meanwhile, said the plane crashed “in a deserted area” in Russia's southern region of Stavropol.
Three crewmembers were rescued after ejecting from the aircraft, and the search for a fourth was launched, as per the ministry. Stavropol Gov. Vladimir Vladimirov, however, said one of the rescued pilots died.
On Christmas Eve, Ukraine claimed to have shot down two Russian fighter jets. In January, the Ukrainian air force said it shot down a Russian early warning and control plane and a key command centre aircraft that sends information to troops on the ground.
Moscow in January also accused Ukraine of shooting down a Russian military transport plane that was carrying Ukrainian Prisoners of War (POW) who were headed for a prisoner swap.
The next month, Ukraine said it knocked out another early warning and control plane.
Meanwhile, Russian missiles struck cities in the central Dnipro region of Ukraine, killing eight people, including an 8-year-old girl, and injuring 25, local officials said.