Vladimir Putin has warned the West that an attempt to interfere with Russia's invasion of Ukraine would lead to "consequences never encountered in your history".
The president of Russia declared that a special military operation would be launched in the east of Ukraine, in separatist areas.
But what followed was a "wide-scale" assault on their Balkan neighbour with multiple missile attacks on the capital Kyiv as well as other cities across the country.
READ MORE LIVE Russia launches 'full-scale' invasion of Ukraine as explosions heard in country
The Mirror reported that he hosted a televised speech at 6am local time, warning: "Whoever tries to hinder us, and even more so, to create threats to our country, to our people, should know that Russia's response will be immediate.
"And it will lead you to such consequences that you have never encountered in your history.
"We are ready for any development of events. All the necessary decisions have been made in this regard. I hope that I will be heard."
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Putin told the Ukrainian military to lay down its weapons and go home, adding: "All servicemen of the Ukrainian army who fulfil this demand will be able to freely leave the combat zone and return to their families".
US President Joe Biden has called Russia's decision to commence a military operation in eastern Ukraine "unprovoked and unjustified."
He said in a statement: "The prayers of the entire world are with the people of Ukraine tonight as they suffer an unprovoked and unjustified attack by Russian military forces.
"President Putin has chosen a premeditated war that will bring a catastrophic loss of life and human suffering.
"Russia alone is responsible for the death and destruction this attack will bring, and the United States and its Allies and partners will respond in a united and decisive way. The world will hold Russia accountable."
The United Nations Security Council called an emergency meeting as European and US officials rushed to impose more economic sanctions on Russia.
The attack comes after Putin moved up to 160,000 troops on the border with Ukraine, but had remained adamant he was not planning an invasion.
Instead, Russia-backed separatists took control of Donetsk and Luhansk on Tuesday and they were declared independent People's Republics.
Kremlin troops were then given the green light to move in and act as supposed "peacekeepers", Putin said.
At the same time the Russian leader claimed any violence has been provoked by Kyiv.
He described the invasion as a "special military occupation" and said he wants to "demilitarise", not occupy, Ukraine.
"I have decided to conduct a special military operation," said Putin.
"Its goal is to protect people who have been subjected to bullying and genocide... for the last eight years. And for this we will strive for the demilitarisation and denazification of Ukraine.
"And to bring to court those who committed numerous bloody crimes against civilians, including against citizens of the Russian Federation."
