Hackers have crippled several major Russian news sites and replaced them with anti-Vladimir Putin messages.
The regular home pages of state news agency Tass, Kommersant and Izvestia were replaced with an anti-war message in support of Ukraine.
The hack was believed to have been carried out by activists Anonymous.
The message read: "Dear citizens. We urge you to stop this madness, do not send your sons and husbands to certain death. Putin makes us lie and puts us in danger.
"We were isolated from the whole world, they stopped buying oil and gas. In a few years we will live like in North Korea.
"What is it for us? To put Putin in the textbooks? This is not our war, let's stop it!
"This message will be deleted, and some of us will be fired or even jailed. But we can't take it anymore.
"Indifferent journalists of Russia."
Hours after Russia launched its offensive on peaceful neighbour Ukraine, Anonymous declared "cyberwar" against the Russian Government in a tweet.
The group wrote: "The Anonymous collective is officially in cyber war against the Russian government."
Last night it claimed responsibility when the government website suddenly went down.
It comes after Russian TV channels appeared to have been hacked and started broadcasting Ukrainian songs over the weekend.
Anonymous declared taking the sites offline as a "present" to Putin after he ignored their earlier demands to resign and restore the rights of the Ukrainian people.
In a message directly aimed at the Russian President, a member of the hacking group said: "We have been patently waiting for you to respond to our most recent request, but we find ourselves growing impatient of your foot dragging.
"Unfortunately it seems you have made the option to ignore our presence and therefore we have decided to dedicate and operation specifically for you.
"A present of sorts."
He then goes on to name other times the group has taken websites offline.
It comes as the European Union announced it was banning Russian state-backed channels RT and Sputnik.
Over the weekend a number of sites Russian government websites, including the official Kremlin and media regulator pages were down, with cyber attacks believed to be to blame.
Earlier this year there were fears Russia may launch devastating cyber attacks on the West.
A former British military intelligence officer told the Mirror: “By their very nature cyber attacks are deniable and can be seen as non-lethal.
“However, apart from crippling defence, energy, business, finance and emergency service infrastructure - all of which can cause deaths, they can be absolutely devastating.
“It fits with Russia’s hybrid warfare ethos - using both direct and indirect conflict to attack and undermine the enemy and it is very likely Moscow will use this.”
European Commission president, Ursula von der Leyen, said: “Russia Today and Sputnik, as well as their subsidiaries, will no longer be able to spread their lies to justify Putin’s war and to sow division in our union.
"So we are developing tools to ban their toxic and harmful disinformation in Europe.”
