EU chief Charles Michel is urging Belarus to "not take part" in Russia's military assault on Ukraine.

There will be an emergency European Union summit to decide new sanctions on Moscow over its invasion later.

In an appeal to Belarus and its people during a media conference at Nato headquarters, Michel says: "You have the choice not to follow Russia's destructive action. You have the choice not to take part in this needless tragedy against your neighbours in Ukraine."

Belarus, a Russian ally that borders Ukraine to the north, is permitting tens of thousands of Russian troops to pour across its border into Ukraine, according to Ukraine's government.

Lukashenko said earlier that Russian President Vladimir Putin had called him to inform him of his military operation against Ukraine. He said that Belarus's own national forces "are not taking part in this operation".

Image source, Reuters

The UN refugee agency says the situation in Ukraine is quickly deteriorating and urged neighbouring countries to keep their borders open to Ukrainians seeking a safe haven.

"We have already seen reports of casualties and people starting to flee their homes to seek safety," says Filippo Grandi, UN high commissioner for refugees.

Several European countries bordering Ukraine are already preparing for the arrival of refugees fleeing the Russian invasion.

Poland is setting up reception points on its border and its hospitals are preparing beds for wounded Ukrainians, says the country’s health ministry.

Hungary and Slovakia both say they are ready to welcome refugees and are sending extra troops to manage the likely influx at additional crossings set up on their borders with Ukraine.

Slovakia's Prime Minister, Eduard Heger, urged: "Please let's have compassion and understanding for them."

Germany has also offered humanitarian help to countries bordering Ukraine.

As Russian attacks on Ukraine continue, journalists on the ground are providing eyewitness reports across the country.

Video and photos show smoke rising above a military airfield near Chuguev in the Kharkiv region of eastern Ukraine. The footage has been verified, but the source is unknown.

The president of the European Commission Ursula Von Der Leyen is speaking in Brussels to outline sanctions to "seriously degrade the Russian economy".

She says:

• We will freeze Russian assets in the EU and stop the access of Russian banks to the European financial market
• The measures will impact Russia severely, increasing capital outflow, raising inflation and gradually eroding its industrial basis
• We will weaken Russia's technological position in key areas from high-tech components to cutting-edge software

We've heard condemnation of Russia's actions from many global leaders - including UK PM Boris Johnson who called it an "act of wanton and reckless aggression". We should be hearing from French President Emmanuel Macron later.

Earlier, Nato secretary general Jens Stoltenberg said allies from North America and Europe have already deployed thousands more troops to the eastern part of the alliance and had placed more on standby.

"We have over 100 jets at high alert protecting our airspace and more than 120 allied ships at sea from the high north to the Mediterranean," he said.

"We will continue to do whatever is necessary to shield the alliance from aggression".

He has called a virtual summit of Nato leaders tomorrow to address the way forward.

"Russia is now facing severe costs and consequences imposed by the whole national community," he said.

He ended by saying that freedom would always prevail over oppression.

Ukraine's president, Volodymr Zelensky says his country's armed forces are repelling attacks in the Donbas area of eastern Ukraine as well as other parts of the country. Russia by contrast says that it has met little resistance.

The Ukrainian military says it has killed about 50 Russian "occupiers" and shot down at least six Russian aircraft, although this has not been independently verified.

There have been reports of Russian strikes on Ukrainian military infrastructure around the country.

The BBC has been able to verify this video, which appears to show a missile attack on an airport in western Ukraine.

French President Emmanuel Macron has said the Russian attack on Ukraine is a "turning point" in European history.

In a televised address to the nation, he says France will stand by Ukraine's side.

Macron adds that Russia's actions will have "durable and deep" consequences for the continent.

The Russian military has put out a statement making a variety of claims about the nature of the invasion and its justifications for it.

It repeats the claim that its assault on Ukraine was launched to protect the Russian-backed separatist areas of the Donbas, which Russia said was being attacked by the Ukrainian military. Experts say this is almost certainly false and Western governments have been warning for weeks that Russia would create a pretext to justify invasion.

Russia also says that its strikes are "high precision" and targeting only military infrastructure. We are seeing reports that more than 30 Ukrainian civilians have been killed, including at least eighteen people near the port of Odessa in a missile attack.

The Russian military also says that the Ukrainian armed forces are fleeing en masse, abandoning their weapons and positions. Ukraine, by contrast, says it has killed about 50 Russian "occupiers" and shot down Russian jets - though this can't be verified. The government has also offered weapons to anyone who wants them.

Francis Scarr, BBC Monitoring, Moscow

The majority of media in Russia is state-controlled - which goes some way in explaining why the country's TV channels are presenting the invasion as an act of self-defence measure aimed solely at taking out Ukraine's military.

Many channels have been quoting a Defence Ministry statement stressing that "high-precision weapons" were being used against Ukrainian military sites, with no threat to civilians.

Official state Rossiya 1 TV began a news bulletin by saying: "Today Russia has begun a special military operation aimed at protecting the people who for the last eight years have been subjected to abuse and genocide by the regime in Kyiv."

Image source, Rossiya 24

Meanwhile, several news bulletins have featured vox-pop interviews in the rebel-held regions in eastern Ukraine with apparently joyous locals.

Official state news channel Rossiya 24 showed two people in Donetsk speaking to a reporter.

"It's magnificent. There are no other words to describe it," one man said.

"I'm really happy. We've waited eight years for this," a woman told the channel.

Lithuania's president has declared a state of emergency, according to the Reuters news agency.

Gitanas Nausėda says he plans to send the army to defend its borders in response to "possible disturbances and provocations due to large military forces massed in Russia and Belarus".

Meanwhile Kaja Kallas, the Prime Minister of Estonia - which borders Russia - has told BBC News "we’re gonna help Ukraine with all the means that we can" including political support and by sending weapons.

Kallas says "we must do everything at EU and Nato level for this aggression not to expand."

She has advised Estonians to stay calm and says there is no threat currently on Estonian borders.

Johnson recognises this is a global crisispublished at 12:26 Greenwich Mean Time 24 February 2022

12:26 GMT 24 February 2022

Rob Watson
BBC political correspondent

This is huge, this is the British prime minister saying "this mission must end in failure".

In other words, it's a recognition that we've moved beyond the Cold War, that this is a moment of global crisis and the idea that this is an attack on freedom and democracy.

Because if you think about it, the UK and the rest of the West are faced with a choice at this point: Do you normalise what Russia has done and accept it no matter how unwillingly?

Or do you really make this about the future of your relationship with Russia, about the future of Vladimir Putin?

And it suggests so far that the UK wants to go down that second path, that this cannot be allowed to stand, that this has to be the West versus Putin.

We've just heard the UK PM say that Vladimir Putin is unleashing a tidal wave of violence on Ukraine.

In the capital Kyiv, people have been fleeing to seek safety, amid fears Russian forces will attack the city.

Two young people who are seeking safety with family elsewhere in the country have spoken to the BBC.

"We will of course do everything to keep our country safe," says Boris Johnson.

We’re joined in our outrage with allies and friends around the world, he adds, saying the UK will work with them for however long it takes to ensure Ukraine's independence and sovereignty is restored.

This "act of wanton and reckless aggression" is an attack on democracy and freedom in eastern Europe and throughout the world, he continues.

He ends by saying this crisis is about the right of a country to choose their own future and that is a right the UK will always defend.

Continuing his televised statement, Johnson describes the Russian attack as a "hideous and barbaric venture of Putin" which "must end in failure".

He says Putin has brought "a tidal wave of violence" to Ukraine.

Directly addressing Russians, Johnson says he can't believe this is being done "in your name" or believe that Russian want a "pariah status" for their country.

Addressing Ukrainians directly, Johnson says: "We’re with you, we’re praying for you and your families."

He said he knows the flame of freedom will "blaze bright again" in Ukraine. "I don’t believe the Russian dictator will subdue the national feeling of Ukranians".

Image source, PA Media

The UK was one of the first countries in Europe to send defensive weapons to help Ukraine, says Boris Johnson.

Other allies have followed suit and the UK will do more in the days ahead, he says, without providing specifics.

"Today in concert with our allies we will agree a massive package of economic sanctions designed in time to hobble the Russian economy," Johnson says.

Europe must also collectively cease the reliance on oil and gas that has given Putin a grip on Europe, he says.

"This is not some faraway country of which we know little," the prime minister says.

He says Ukraine - the second-largest country in Europe - is one that for decades has enjoyed freedom and democracy.

"We cannot allow that freedom to be snuffed out. We cannot and will not look away."

Boris Johnson says that after 04:00 GMT he spoke to President Zelensky of Ukraine to offer the support of the UK.

He says our worst fears have come true and all the warnings of a Russian invasion have proved tragically accurate.

President Putin of Russia has unleashed war in Europe, he says. He says Putin has attacked a friendly country without any provocation or credible excuse.

Bombs have been raining down on an entirely innocent population, Johnson continues.

"A vast invasion is under way by land by air and by sea."

Image source, Reuters

More now on the black smoke seen rising over the Ukrainian defence ministry intelligence headquarters in central Kyiv which we told you about a short while ago.

We understand the building appears to be intact, and the smoke actually appears to come from a large fire next to the building. Witnesses have seen uniformed people throwing bags on to the fire.

Ukraine says some of its military command centres have been hit by Russian missile strikes.

Just outside Kyiv, in the town of Brovary, authorities say at least six people were killed by a series of missile strikes.