Hackers took over Russian state media on Thursday to tell listeners to rush to nuclear bomb shelters and take anti-radiation pills.
Radio and television broadcasts in Moscow and the western Sverdlovsk area were interrupted with a phony warning of a missile strike on the country.
The Kremlin blamed the false alarm, which told listeners to take potassium iodine, put on gas masks and seek shelter, on a cyber attack.
“Urgent message. There was a strike,” a Russian voice boomed, while television viewers were presented with a map of Russia being covered in red.
“Urgently go to a shelter,” the voice declared. “Seal the premises. Use gas masks of all types.”
The Telegraph reported that after the message was broadcast, screens displayed a black and yellow radiation warning symbol.
“A false air raid alert was broadcast in Moscow after servers of radio stations and TV channels were hacked,” said the Kremlin’s emergency ministry.
There has been no claim of responsibility for the latest cyber attack with it possibly originating from Ukraine dissidents or potentially Russian
It was the third time in the past month that Russian broadcasters have been targeted. Last month a false warning was released in the Crimea urging caution against an incoming missile attack. For this event, Ukraine was blamed. A similar broadcast was run a week later during Vladimir Putin’s state of the union address.
Ukraine has not taken responsibility for any of the alleged cyber attacks.
Meanwhile, Ukraine's capital has restored most of its power supply, officials said, as the country responds swiftly and defiantly to the latest Russian missile and drone barrage targeting critical infrastructure.
In what has become a familiar Russian tactic since the autumn, the Kremlin's forces hit Ukraine from afar amid months of a grinding battlefield stalemate on the front line in eastern areas.
The apparent aim is to weaken Ukraine's resolve and compel the Ukrainian government to negotiate peace on Moscow's terms.
Ukrainian authorities scrambled to counter the bombardment's consequences, part of a recurring cycle of urban smash-and-repair which has brought little change in the course of the war.
The Institute for the Study of War, a Washington-based think tank, said in an assessment "these missile strikes will not undermine Ukraine's will or improve Russia's positions on the front lines".
Ukrainian military analyst Oleh Zhdanov said the Russians are striking civilian infrastructure because they cannot efficiently target Ukrainian military assets.