Words by News Editor Emma Burrows and video report by Correspondent Neil Connery, who are both in Moscow and report on a landmark day in Russia's history
Shortly before dawn, Russian President Vladimir Putin announced a military operation against Ukraine.
Russians woke to the news that their country was involved in a "special operation" to "demilitarise" their neighbour.
The sense of shock in Moscow was huge. I asked lots of people what they thought about President Putin's decision - business people, analysts, politicians - many simply could not find the words or refused to talk.
"I have nothing to say, I am completely devastated," someone who advises the Kremlin on foreign policy told me, declining an interview.
"I am in deep shock, I can't believe my eyes, I can't believe my ears. It's a really tragic moment for Ukraine and for Russia as well. Russia from the point of view of the whole world is turning into a pariah state like Iran or North Korea," said Mikhail Fishman a leading Russian journalist and TV anchor for independent channel Rain.
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On state Russian television, there is none of that sentiment. The broadcasts suggest a "special operation" is being carried out in the Donbas in eastern Ukraine.
TV here gives the impression the operation is targeted and limited and Russians are not being shown the full enormity of what is unfolding.
There is little mention of attacks across Ukraine, including in the country's capital Kyiv.
Emma Burrows shares the latest military assessment by a Ukrainian official who explains the key combat areas, the number of Russian battalions in the field and claims the Russians have "low morale"
Putin's spokesperson Dmitry Peskov said he expects most Russians to support the president's decision.
Speaking this morning in Moscow, one woman said she wasn't prepared to talk on camera because I wouldn't like what she had to say. "I have family there in the Donetsk and Luhansk regions (of Ukraine) and I think this is right. This needs to be done to help our people," she said.
"If this is in the interest of Russia, then I support it," another person said.
Other Russians also refused to talk on camera - for more chilling reasons. They were shocked, stunned and devastated but worried that if they spoke out directly against Vladimir Putin, they might lose their jobs, their businesses or their study opportunities.
One leading Moscow theatre reportedly sent a notice to actors forbidding it from making "any comments at all" about Russia's invasion of Ukraine, as the city's culture department allegedly says any negative comments will be considered "treason of the motherland".
Across Russia, however, thousands of people braved arrest and turned out on the streets shouting "no to war!" In Moscow, heavily armed riot police were waiting for the protesters, flooding a central square at an unsanctioned protest clothed in riot gear and carrying batons.
In Russia, protests are forbidden without approval from the authorities. The independent monitoring group OVD Info says thousands of people have been detained across the country from Siberia to St Petersburg for protesting against Vladimir Putin's decision to invade Ukraine, "a country where we have brothers and sisters".
"I don't agree with what Putin is doing. It's awful, it's immoral, how can you behave like this?" One young woman, almost crying with emotion, told me.
Vladimir Putin has long planned his assault on Ukraine and has clearly factored in the cost of sanctions and international condemnation.
It seems questionable that external pressure will make him pull back his troops from Ukraine and, at this stage, internal anger against a widely popular president is unlikely to do it either.
In the last years here, the main opposition leader has been poisoned and imprisoned, independent media have been labelled 'foreign agents' and many opposition figures have fled abroad.
Vladimir Putin has faced down far bigger numbers of demonstrators than those who took to Russia's streets tonight to voice their hurt, horror and fury.
The day started with a nationwide broadcast with the president talking about what he called the 'denazification of Ukraine.'
By the end of it protesters were chanting 'Gestapo' on Moscow's streets as the police moved in to arrest them.