We're ending our live coverage of the Ukraine crisis for today.

Here's a recap of some of the key events today:

• US President Joe Biden has warned that Russia is trying to engineer a pretext to invade Ukraine, and that the threat of an attack is "very high"
• Moscow has called the claims "baseless" and has released a strongly worded letter saying Washington is ignoring its security demands and threatening "military-technical measures"
• Russia has insisted it is moving troops away from the Ukrainian border, but new satellite images show wide-scale Russian military activity persists close to Ukraine's borders
• Meanwhile, Ukrainian forces and Russian-backed separatists have traded fire in eastern Ukraine
• Three people were injured when a nursery was struck by what Kiyev says was a shell fired by the rebels

Here's our main story on Biden's comments today.

Image source, Getty Images

Image source, Getty Images

Russia delivered a list of demands to the US ambassador on Thursday, accusing Washington of ignoring its security demands.

“No ‘Russian invasion of Ukraine’, which the United States and its allies have officially been announcing since last fall, is happening, nor is one being planned,” says the letter from the Russian Foreign Ministry.

"In the absence of the readiness of the American side to agree on firm, legally binding guarantees of our security from the United States and its allies, Russia will be forced to respond, including through the implementation of military-technical measures," the lengthy document says.

It called the US refusal to commit to never allowing Ukraine to join Nato "not constructive" and called for Nato troops to pull back to countries that joined the alliance before 1997.

"We insist on the withdrawal of all US armed forces in Central Europe, Eastern Europe and the Baltics," it added.

The letter adds that Russia is prepared to negotiate on arms control treaties, and the possible Russian inspection of US missile bases in Poland and Romania, but only if its security concerns are addressed.

“We welcome the readiness of the United States for appropriate consultations,” the document says, adding: “This work cannot replace the settlement of the key problems posed by Russia.”

The US did not immediately respond to the list of demands.

Image source, Getty Images

The UK is scrapping a fast-track visa scheme for foreign investors over "security concerns" amid concerns of illicit Russian money in Britain.

The Tier 1 investor visas had allowed residency in the UK for those investing at least £2m, but new applicants will no longer be accepted.

The announcement had been expected next week amid pressure on ministers to cut UK ties to Russia over the threat of invasion to Ukraine, with a source confirming the decision to the BBC on Wednesday.

Foreign Secretary Liz Truss says the Tier 1 scheme is being closed to "clamp down on illicit finance".

"This kind of malign activity, including what we are seeing from Russia right now, has no place in the UK," she says.

Read more on this story here.

More details are emerging of the reported shell blast that struck a kindergarten in eastern Ukraine.

Three staff at the nursery were injured when a projectile - which Ukraine says was fired by Russian-backed separatists - blew a whole in a wall.

A mother of a child at the kindergarten says she and her husband rushed to the kindergarten in a panic when they heard about the strike in the village of Stanitsya Luhanska.

Image source, Getty Images

The woman, who refused to give her name, told AFP news agency: "I was very scared. The kindergarten has no bomb shelter. It only has thick walls. But they even managed to puncture those. I still can’t calm down."

Natalia Slesareva, who works at the kindergarten, said it was a close call that everybody escaped unharmed.

"The children were eating breakfast when it hit," she told AFP.

"It hit the gym. After breakfast, the children had gym class. So another 15 minutes, and everything could have been much, much worse."

Image source, Getty Images

Image source, Getty Images

In the past few hours:

• The US Secretary of State has told the United Nations that Russia is still plotting an excuse to invade Ukraine
• "It could be a fabricated so-called terrorist bombing inside Russia, the invented discovery of a mass grave, a staged drone strike against civilians, or a fake - even a real - attack using chemical weapons," said top American diplomat Antony Blinken
• Satellite images have emerged showing continued Russia military activity around Ukraine's borders, and a field hospital that may indicate that the forces are planning for battle-related injuries
• Russia warned the US in a letter that Washington was ignoring the country’s security concerns
• "In the absence of the readiness of the American side to agree on firm, legally binding guarantees of our security from the United States and its allies, Russia will be forced to respond, including through the implementation of military-technical measures," the document says
• President Joe Biden told reporters: "We have reason to believe they are engaged in a false flag operation to have an excuse to go in. Every indication we have is they're prepared to go into Ukraine and attack Ukraine".

We've been hearing a lot about the Minsk agreements as tensions escalate over the crisis.

The agreements - named about the capital of Belarus where they were signed in 2014 and 2015 - are designed to keep a ceasefire between the Ukrainian government and Russian-backed separatists in eastern Ukraine.

Among the deal's 13 points are a ceasefire, the withdrawal of heavy weapons, and the withdrawal of "all foreign armed formations, military equipment and also mercenaries" from Ukraine.

They also give special status to the separatist-controlled regions of Luhansk and Donetsk and give the Ukrainian government "full control" of Ukraine's border with Russia.

But there are fundamental differences in how the agreements are interpreted by Kyiv and Moscow.

While Ukraine sees the agreements as the basis for reuniting Ukraine and re-establish its sovereignty, Russia sees them as a chance to grant autonomy to the separatist territories. The agreements have never been fully implement by both sides.

Read more: What are the Minsk agreements?

Frank Gardner
BBC Security Correspondent

Image source, Maxar

The latest satellite images provided by the US space technology company Maxar show that wide-scale Russian military activity persists close to Ukraine's borders, despite recent Russian claims of de-escalation and withdrawal.

Taken in mid-February, they illustrate that Ukraine remains surrounded on three sides - on its borders with both Russia and Belarus - by Russian military hardware and troop concentrations.

Image source, Maxar

It is important to remember that Russia's current military presence of around 30,000 troops in Belarus, while alarming to both Ukraine and NATO, are part of joint, scheduled exercises that are due to conclude on February 20.

So a key test of Moscow's intentions will come after that date when satellite images will reveal if the bulk of Russian forces there have remained or departed.

Satellite images show Russian military activity

Russia says it ordered the expulsion of the deputy ambassador at the US embassy in Moscow in response to the US expulsion of a senior official at the Russian embassy in Washington.

Earlier the US called the expulsion of its senior diplomat, Bart Gorman, "unprovoked" and an "escalatory step".

The Russian foreign ministry has issued a statement in response to what it said were media reports presenting it as "almost a deliberate escalation on the Russian side".

The statement says: "The American diplomat was indeed ordered to leave Russia, but strictly in response to the unreasonable expulsion of the Minister-Counsellor of our Embassy in Washington, despite his status as a leading official".

Ukrainian-born residents in the south of England say they are worried about family still living in the country.

Hanna Greentree lives in Fareham with her husband and daughter, but her 65-year-old mother lives on her own in Ukraine.

Khrystyna Chelak moved to the UK 15 years ago and lives in Caversham but still has family in Ukraine. She says some people are making preparations to leave and have found their nearest bomb shelters.

Watch what they have to say below.

Barbara Plett Usher
State Department Correspondent, BBC News

Earlier today, US Secretary of State Anthony Blinken stopped by the UN Security Council en route to Munich to deliver a dire warning about Russian plans to invade Ukraine.

He ignored admonitions by the Russian ambassador to avoid making a “circus” out of the meeting by “playing to the cameras” with such “speculation".

His speech was the latest installment of the administration’s aggressive information war. It’s made a strategic decision to go public with intelligence, believing that calling out Russia’s so-called “playbook” at every opportunity could serve as a deterrent to conflict.

But Blinken was clearly mindful that such interventions carry risks.

He made a nod to one of his predecessors, Colin Powell, who’d argued a case for invading Iraq in 2003 which turned out to be false.

“Let me be clear,” he said. “I am here today not to start a war but to prevent one.”

The US would be relieved and would gladly accept any criticism about its rhetoric if Russia did not invade, he said.

In the meantime, he laid out clearly, step by step, how US intelligence believes Russia could carry out an attack, starting with manufacturing a pretext to raining bombs and missiles on Kyiv.

Image source, Russian Defence Ministry/TASS via Getty Images

It's quite easy to lose track of what's been going on with all those military exercises near Ukraine's borders in recent days, with countless claims and counterclaims voiced by different players.

Here's a timeline to get you up to speed:

- From 10 February, Russia has been holding massive drills on the territory of its key ally Belarus, Ukraine's northern neighbour

- US officials have warned that up to 30,000 Russian troops may have been involved in the drills, which are set to end on 20 February

- Russia has also massed troops along Ukraine's eastern border, and has been holding exercises in Crimea - a southern Ukrainian peninsula seized by Moscow in 2014

- Russia has since said that some of troops have been returning to their permanent bases - but Ukraine and its Western allies are sceptical

- In addition, from 13 February the Russian Navy has been staging firing exercises in the Black Sea. The drills are set to end on 19 February

- Meanwhile, Ukraine - fearing that it could be encircled from the north, east and south - has been staging its own military exercises across its territory

- Ukraine has also been boosting its territorial defence - weapons-trained civilian volunteers who could be called in case of a foreign invasion

Fergal Keane
BBC News, Northern Ukraine

The Ukrainian border guards scan the snowy forest for any sign of Russian movement.

They stand guard at the Senkivka crossing, where the Kremlin once celebrated the unity of the Soviet world.

A few truck drivers heading south to the capital, Kyiv, cluster near the Three Sisters monument - a white obelisk erected back in 1975 to mark where the borders of Ukraine, Russia and Belarus meet.

Maj Sergiy Khomenko, 29, comes from a military family and grew up in a border village. The current crisis with Russia would have been unimaginable in his parents' youth.

But he serves a Ukraine that has been consistently pushing away from the orbit of Moscow.

"The independence of Ukraine is enshrined in all our documents. It is in our constitution. As a military man, I need to protect this," he tells me.

Read the story in full here.

In a video posted to its official Twitter account, the UK's Ministry of Defence (MoD) has warned that "a considerable number of civilians will die" if Russia chooses to attack Ukraine.

In a video update posted on Thursday, the MoD said that it has seen no evidence to substantiate Russian claims that its forces are withdrawing from the border region and "can conduct an invasion without further warning".

The video also outlined a number of reasons that Russian President Vladimir Putin would want to launch a military operation in Ukraine, including a belief that is it is a "strategically important buffer zone" between Russia and Nato, as well as its cultural and historical ties to Russia.

"It [Russia] does not accept Ukraine as an independent state," the video's narrator says. "But it is an independent state".

The Russian forces amassed on Ukraine's borders are "beyond anything needed" for large-scale military exercises and could directly threaten Kyiv, the MoD video said.

"Defence intelligence assesses that [Putin] would be willing to sustain thousands of casualties to get what he wants," it warned.

The MoD ends with the message that Putin "can still choose peace" and diplomacy to de-escalate tensions.

While tensions mount, the US government has urged its citizens to leave Ukraine immediately, citing the threat of an imminent Russian invasion. But not all US citizens who live in Ukraine are taking this advice.

Many here don't believe that a full-scale attack on Kyiv is imminent, despite warnings from intelligence sources quoted in the media.

BBC News Ukraine has spoken to some Americans living in the country, including businessmen, teachers and volunteers, and asked them about their decision to stay.

Image source, Sean Almeida

Sean Almeida, from Boston, has been building a business in Kyiv since 2014, and now, despite the threat, does not intend to flee Ukraine.

"Let Biden say what he wants, but I am not going to panic and leave the country that has long since become my home," he says.

Read more here: 'This is our home': The Americans who refuse to leave Ukraine

Reporting by Oleh Chernysh, BBC News Ukrainian, Kyiv

Russia's response to US offers little sign of a diplomatic breakthroughpublished at 17:24 Greenwich Mean Time 17 February 2022

17:24 GMT 17 February 2022

Steve Rosenberg
BBC Moscow Correspondent

Any sign of a breakthrough in East-West diplomacy?

Not if Russia’s eleven-page written response to Washington’s proposal is anything to go by.

The letter is full of criticism of the United States. The tone is bitter, impatient and pretty uncompromising.

Moscow detected “no constructive answer” from the US to Russia’s key demands, such as an end to Nato enlargement eastwards.

Russia is not softening its stance. It’s insisting that all US troops and weaponry be withdrawn from central and eastern Europe, south-eastern Europe and the Baltics. Hard to see America agreeing to that.

Then came the threat. It’s one that President Putin has already delivered: that if Moscow fails to receive the “legally binding security guarantees” it seeks, it will react with “military-technical means.”

What would those be? Moscow’s not saying - intentionally. To keep the West guessing.

Today’s expulsion of the deputy US ambassador to Moscow adds to the general sense of diplomacy stalling. Washington interprets the move as an escalation.

Russia doesn’t want to be seen to be closing the door to dialogue. And there are some areas – like arms control and risk reduction – where common ground could be found. But Moscow has made it quite clear its main concerns have not been addressed.

BBC Monitoring
The world through its media

We've had reaction from the Kremlin in response to the US president's comments earlier. Spokesman Dmitry Peskov has criticised Joe Biden for saying that Russia may launch an attack on Ukraine "within the next several days".

In remarks reported by the state RIA Novosti news agency, Peskov said: "Unfortunately, tension continues to be whipped up with such statements."

Image source, EPA

UK Europe Minister James Cleverly tells the UN Security Council Russia is using "increasing disinformation" to "fabricate a pretext" to invade Ukraine.

"We are seeing increasing disinformation about events in the Donbas that are straight out of the Kremlin playbook," he says.

"A blatant attempt by the Russian Government to fabricate a pretext for the invasion of Ukraine."

Western allies have warned that recent reports of shelling in Ukraine's south-eastern Donbas region could be part of a Russian "false-flag" operation to justify an invasion.

Image source, Reuters

UK Europe Minister James Cleverly is also in New York addressing the UN Security Council. He says we're at a "critical juncture to prevent further escalation".

"Russia has deployed the forces necessary to invade Ukraine and now has them readied for action," he says.

Despite Russian claims its forces are withdrawing, "the opposite is in fact true and the Russian military build-up continues", Cleverly says.

"Russia is patently failing to live up to the international commitments that it has made around military transparency by refusing to adequately explain its military build-up or to provide the necessary transparency to build trust or to de-escalate the situation."

Image source, Reuters

We've heard more from US Secretary of State Anthony Blinken, he tells the UN Security Council in New York that he has offered to meet with Russian Foreign Minister Sergei Lavrov in Europe next week.

Additionally, Blinken says the US is proposing a meeting of the Nato-Russia council and permanent council of the Organization for Security and Co-operation in Europe, in a bid to resolve the tensions on Ukraine's borders "without conflict".

These meetings, Blinken adds, could "pave the way" for a summit of key leaders to discuss mutual security concerns.

"As lead diplomats, we have a responsibility to make every effort for diplomacy to succeed and leave no diplomatic stone unturned," he says.

Blinken adds that the US believes that the implementation of the Minsk Agreement is vital to ensuring a diplomatic path forward.

He says the US would be "relieved" if its warnings about Russia are incorrect and US predictions proven wrong.