Media channels in Ukraine and Russia reported on Monday morning of the dramatic elimination of a senior figure in Russia.
The assassination occurred in a luxurious building in Moscow, about a 20-minute drive from the Kremlin, the official residence of Russian President Vladimir Putin.
The identity of the senior official has not yet been released, despite the fact that he was surrounded by bodyguards.
Several independent journalists estimated that the murdered man was Arman Sargsyan - wanted by Ukraine and founder of the 'Arbat' battalion, which is affiliated with the Russian army and is fighting against Ukraine in the area of the Kursk Oblast.
The senior figure lived in the luxury residential complex "Scarlet Sails" and a security guard at the entrance to the building told an independent media source in Russia that he had seen him appear several times on national television.
Ukrainian media reported that the assassination was carried out by detonating an explosive device in the area of the elevators in the building.
At the end of last year, the commander of the Russian army's radiological, chemical and biological defense unit, General Igor Kirillov, was assassinated in Russia.
Russian media reported that the explosion was caused by a bomb planted in an electric scooter at the entrance to his home in an apartment building in the Ryazansky district of Moscow. Two of his deputies were also killed in the explosion.
Kirillov, 54, served in his position for the past seven years and is responsible for publishing many reports accusing Ukraine and the US of using chemical weapons during the war declared by the Russians against the Ukrainians.
He also accused the US of operating a vast network of biological laboratories in Ukraine and other locations, which he said pose a threat to the civilian population.