EU leaders will hold an emergency summit in Brussels tomorrow to discuss the Russia-Ukraine crisis.

In a letter to EU leaders, the head of the EU Council, Charles Michel, writes: "It is important that we continue to be united and determined and jointly define our collective approach and actions."

He says Russia's "aggressive actions" have violated "international law and the territorial integrity and sovereignty of Ukraine".

"They also undermine the European security order," he writes. "The use of force and coercion to change borders has no place in the 21st Century."

Image source, UN

Ukraine's Foreign Minister goes on to tell the UN the situation in the Donbas region has already been terrible for people living there for years.

Dmytro Kuleba highlights the "infamous" Izolyatsia prison in Donetsk, which he says has subjected hundreds of people to heavy forced labour, torture and humiliation.

"It continues to function as a literal concentration camp, in Europe in the 21st Century," says Kuleba.

He goes on to say Ukraine is defending not only global security - but freedom, democracy, fundamental principles of international law and peaceful life.

"The future of millions of people in Europe and around the globe rely on the rules that Russia tries to destroy," he says.

He also talks about Crimea (which was annexed by Russia in 2014) - saying he disagrees with the Russian view that it is "case closed". Political persecutions continue there unabated, he says - and since 2014 more than 64,000 Ukrainians have had to leave because of fears of persecution or discrimination.

Ukraine's Foreign Minister, Dmytro Kuleba, has been speaking at the United Nations General Assembly, calling for "swift, concrete and resolute actions".

He says we're at a critical juncture in world history - and the world's actions today will define it for decades to come.

He says we've all read about the mistakes that politicians made in the run up to other world wars - and urges countries not to repeat the mistakes of the past.

Russia's accusation that Ukraine has been escalating the situation is absurd, says Kuleba. "Russia's statements are outrageous and horrific and go far beyond threatening Ukraine."

He points to Vladimir Putin's speech earlier this week when he said Ukraine has no right to exist.

"Anyone who thinks I exaggerate should just watch this horrifying speech," he adds.

More now on the breaking news that Ukraine has been targeted by a large scale cyber-attack.

Digital Transformation Minister Mykhaylo Fedorov wrote on telegram that services for several Ukrainian institutions, including the health, veterans and foreign ministries, have been taken offline in a so-called DDOS attack.

He added that several banks have also been affected by the outage.

DDOS attacks, or Distributed Denial of Service, aim to overwhelm websites by flooding a network with fake traffic and preventing it from communicating as it normally would.

Ukrainian authorities said this week they had seen online warnings that hackers were preparing to launch major attacks on government agencies, banks and the defence sector.

As we just told you, UK Defence Secretary Ben Wallace has said the Russian president has gone "full tonto" over actions ordering troops into Ukraine.

You can watch his comments below.

Websites belonging to a host of Ukrainian governmental bodies have been targeted in a massive cyber-attack, Digital Transformation Minister Mykhaylo Fedorov has said.

Websites for the Ukrainian parliament (the Rada), the foreign ministry and the security services are among several services that have been affected by the attack.

Image source, PA Media

Vladimir Putin has gone "full tonto" over Ukraine, UK Defence Secretary Ben Wallace has suggested.

He says the Russian president has made the mistake of having no allies in supporting his actions, comparing him to Tsar Nicholas I.

Wallace, a former Scots Guards officer, argues his regiment "kicked the backside" of Tsar Nicholas I in the mid-19th century Crimean war, adding "we can always do it again".

The minister made the comments while speaking with serving military personnel in Westminster.

He says: "Unfortunately we've got a busy adversary now in Putin, who has gone full tonto."

Wallace also says the UK has 1,000 personnel on stand-by to respond to the crisis,

"Tsar Nicholas I made the same mistake Putin did... he had no friends, no alliances," he adds.

Jenny Hill
BBC Berlin correspondent

Vladimir Putin has "smashed the Minsk agreement to pieces", the German foreign minister Annalena Baerbock has said today. The Minsk agreements are a long-standing ceasefire agreement in eastern Ukraine (more here).

But she vowed to keep the possibility of dialogue open using the Normandy format as well as other frameworks.

Speaking at a press conference with her French counterpart Jean Yves Le Drian in Berlin, Baerbock said President Putin was trying to turn back the wheel of history.

The foreign secretaries said Europe had implemented only the first of several levels of sanctions and was ready to trigger more if necessary.

But they insisted they were determined to keep diplomacy going.

"The hand is still stretched out," said Le Drian.

Image source, PA Media

Home Secretary Priti Patel says the UK's opposition to President Putin's aggression against Ukraine is likely to have consequences at home.

Patel says the warning lights for Russia have been "flashing red" for several years.

"Look at Salisbury, look at the cyber-attacks", she says, "just look at attempts to interfere in our democracy".

The home secretary adds: "The risk is alive. And on that basis, we are absolutely stepping up everything that we need to domestically."

It is understood no new specific threats to the UK have been identified as a result of the current situation in Ukraine.

But the National Cyber Security Centre has urged businesses to ensure their cybersecurity measures are up to date.

There's been a lot of news in the past few days and it's easy to lose track of where things stand on the Ukraine crisis. So here's a brief recap:

Rebel regions: Russian troops have been massed on Ukraine's borders for months but things escalated on Monday when Vladimir Putin recognised the Russian-backed, rebel-held areas of Donetsk and Luhansk as independent - and even challenged the historical right of Ukraine to exist.

Sanctions: Major Western powers and their allies have responded with a fresh package of measures against Moscow - targeting Russian individuals and banks linked to Putin's regime, and suspending a major new gas pipeline between Russia and Germany. But many say they don't go far enough. There's been particular criticism that the UK is not doing enough to tackle Russian money in the City of London. But the government says it's ready to hit Russia with harder measures.

Next move, Putin: Although he has ordered troops into the two separatist regions of Ukraine to "maintain peace", there is still no clear evidence that any new Russian forces have arrived. This morning Putin insisted he was still open to "direct and honest dialogue" - but experts say his actions in recent days could suggest the crisis will only continue to deepen.

Meanwhile in Kyiv: As the risk of conflict rises, Ukraine has announced a state of emergency and urged its citizens to leave Russia immediately. It's also mobilised reservists to bolster the army. Ukraine's president has called for tougher sanctions on Moscow - warning the "future of European security" is being decided in his country's standoff with its neighbour.

Carrie Davies
BBC Moscow Correspondent

Today is a public holiday in Russia, dedicated to the armed forces.

In Rostov-on-Don, less than 100km (62 miles) from the Ukrainian border, teenage school children parade around the public square. They wear military style uniforms, but march in their school shoes.

At the city’s World War Two memorial, visitors lay red carnations around the eternal flame, and share with us some of their thoughts on the situation in Ukraine.

"Of course it’s scary", one woman tells me as her children pull her hand to go. "But what can we do? We can do nothing."

Image source, EPA

Others are more bullish. One man in his 80s tells me he served in the Soviet fleet. He agrees with President Putin’s decision to recognise the rebel-held areas, as he thinks it will stop Ukraine from shelling. If they don’t, he says, "as they say on TV, we will send in the troops".

Ukraine has repeatedly denied it is starting an offensive against the separatist-held region.

But exactly what will happen next is still up to the president. On this day, known as Defenders of the Fatherland Day, President Putin has kept everyone guessing about how he plans to use them.

BBC Monitoring

Russia's embassy in Kyiv has started evacuating diplomats from Ukraine.

Both the Russian news agency TASS and AFP have confirmed the evacuation after the Russian Foreign Ministry announced the decision yesterday.

Spokeswoman Maria Zakharova said it was due to "multiple attacks" on Russian diplomatic missions across Ukraine and "the aggressive actions" against Russian diplomats.

TASS reports a source at the embassy saying earlier today that "the evacuation of the personnel has already started".

This comes a day after lawmakers in Moscow granted President Putin permission to use force abroad.

Iain Watson
Political correspondent

A range of senior Conservatives from across the party – from Foreign Affairs Committee Chairman Tom Tugendhat to former leader Iain Duncan Smith – are sceptical about whether the government is doing enough on sanctions.

But there has been no attempt to undermine the prime minister today at PMQs, by joining opposition calls to do more, and backbenchers have largely asked about constituency issues.

However, that doesn’t mean their doubts have somehow been dissipated.

Image source, PA Media

• UK Prime Minister Boris Johnson began by telling MPs the UK would shortly be providing military support to Ukraine including lethal aid in the form of defensive weapons and non-lethal aid
• Opposition Labour leader Keir Starmer urged the PM to "unleash a full package of sanctions" against Russia and said the PM should order a review into the licence of Russian broadcaster RT

• Johnson promised there would be more sanctions and said the culture secretary had asked Ofcom to review RT
• The PM also said his government would be taking steps to make property ownership more transparent
• SNP Westminster leader Ian Blackford accused the Conservatives of allowing " a sewer of dirty Russian money" to run through London. He also accused the Tories of raising £2.3m from "Russian oligarchs" and asked the PM if the money would be returned.
• Johnson said his party did not raise money from Russian oligarchs
• Labour MP Margaret Hodge said the sanctions regime was a "mess and a muddle", noting the PM and his ministers had made conflicting statements about whether the UK had the power to sanction members of the Russian parliament

Sergey Goryashko
BBC Russian in Moscow

Vladimir Putin has been speaking this morning, and again says diplomacy is still on the table and he's open for any negotiations.

But he claims Russia's security will be the most important thing for the Kremlin and they will not give up anything.

Today's speech from Vladimir Putin was quite a regular one.

But still I can't say there's been a great patriotic reaction as there was back in 2014 when Russia annexed Crimea.

I suppose some people are still quite puzzled about what this decision to give independence to the so-called people's republics will mean to Russia and what will happen in terms of sanctions.

Because the crisis of 2014 and 2015 was quite significant in terms of its impact on people's wealth, and this one with even more strict and severe sanctions could be even greater.

Paul Adams
BBC diplomatic correspondent

If Russia does decide to launch a full-scale invasion of Ukraine, many experts believe it will be preceded by a massive virtual attack: hacking and other cyber operations designed to disrupt Ukraine’s government and critical national infrastructure.

So far, western officials say recent Russian cyber activity against Ukraine has been "consistent with a previous pattern".

In mid-January, a cyber attack hit 70 central and local government websites, leaving many of them crudely defaced. A message appeared, warning Ukrainians to "prepare for the worst".

Last week a distributed denial-of-service (DDoS) attack hit Ukrainian banks and the Ministry of Defence.

A Ukrainian cybersecurity official called it the largest attack of its kind in the country’s history.

“Ukraine has experienced probably more cyber activity than almost any other country,” a western official told me this morning. "They are very, very used to this."

“We’ve not seen something that’s taken it to a completely different level,” the official said.

But officials say they are watching the situation very closely.

As we've previously reported, Labour leader Keir Starmer has called on the UK government to review the broadcasting licence of Russian broadcaster RT.

Starmer called the network Vladimir Putin's "personal propaganda tool" and questioned whether it should be permitted to continue to broadcast in the UK.

You can watch his exchange with Prime Minister Boris Johnson below.

Iain Watson
Political correspondent

The Labour leader has stressed the need for Parliament to stay united but there are guffaws from the Conservative benches as time and again the scale of the sanctions has been questioned by Labour.

But the PM maintains a more statesman-like stance by thanking the opposition for "broad support".

The SNP's Westminster leader Ian Blackford's political attack accusing the Conservatives of raising cash from Russian oligarchs is more blatant.

It's denied by the prime minister but it has been essential for Boris Johnson to stress he is willing and ready to go further on sanctions.

That message will be aimed at many of his own backbenchers and the opposition.

Labour's Margaret Hodge notes that yesterday the PM said the UK could sanction members of Duma, the Russian parliament, with his new sanctions package.

However in contrast, she says a foreign minister has said Duma sanctions could be introduced through pre-existing rules, while the foreign secretary said the legislation to target Duma members could "take weeks".

"Who is right," she asks, adding: "How can we say we are sounding strong against Russian aggression when our sanctions response is such a muddle and such a mess."

Boris Johnson replies that his government is "putting together the biggest package of sanctions the country has ever produced" which would impact Duma members.

Reality Check

At Prime Minister’s Questions, Boris Johnson has addressed the question of Russian money in the UK, saying he plans to “peel back the façade of beneficial ownership of property in the UK”.

He’s proposing a register of beneficial ownership, which would make it easy to find out who ultimately owns or controls any UK property and who benefits from it.

Many properties in the UK are owned by companies incorporated in places such as the British Virgin Islands, making it hard to find out who really owns them.

The register has been promised for a long time.

The Conservative government said it would introduce such a register in 2016, but did not do so. Lord Faulks, a former Conservative justice minister, has said , externalDowning Street under Theresa May "leant on him" to stop him introducing such a measure in 2017 and then again in 2018.

The government also mentioned such plans in the Queen’s Speech in 2019, but it has not yet happened.

Today, Boris Johnson indicated it would be in the Economic Crime Bill – which he said he would be “accelerating” and would happen “in the next session”, which is expected to start in May.

You can read more about it here.