What does Biden's visit to Ukraine mean - and how will Russia spin it? Sky's experts assess US president's trip to Kyiv
Joe Biden has made his first trip to Ukraine since the country was invaded by Russia almost exactly a year ago.
The president promised a new military aid package worth $500m (£415m), on top of the more than $50bn already provided in US assistance, and was seen walking around the capital Kyiv with his Ukrainian counterpart, Volodymyr Zelenskyy.
Sky's experts analyse the visit - what it means, and how it will be spun by the Kremlin.
Biden's visit could strengthen Putin's resolve
By Diana Magnay, Moscow correspondent
The US President's trip to Kyiv would not have come as a surprise to the Kremlin, given there was considerable speculation that Joe Biden might tag Kyiv to his Poland trip.
Plus shortly before the visit, the White House informed the Kremlin of the trip for 'deconfliction purposes', though with just a few hours' notice.
This visit is a strong symbol to the Kremlin that the US and its allies stand firmly alongside the Ukrainian people and will continue to do so, in the words of the US president, for 'as long as it takes'. President Vladimir Putin did not understand that one year ago, but he probably does now.
Have no doubt that this will be spun to suit the Kremlin's narrative purposes. The images of the US president alongside his Ukrainian counterpart will be construed as further evidence that Ukraine does Joe Biden's bidding.
Where Mr Biden says this war is about "freedom and democracy writ large", Russia spins it as an attempt to redraw the world order to counter US hegemony.
Where the US president stresses the unity of world leaders standing up to help Ukraine in its hour of need, Russia will point to the support it supposedly has from what it has termed the "global majority".
This will be a busy week for Vladimir Putin. He makes a long-anticipated address on Tuesday to the federal assembly. The following day he is expected at Moscow's Luzhniki stadium where he will address cheering crowds presumably, if past form is anything to go on, bussed in from state companies and handed out flags to wave.
Then there is the Defender of the Fatherland day, another key patriotic moment in the Russian calendar.
And finally on Friday, the anniversary of the war. That provides Vladimir Putin with ample opportunity to send a message to his people that Russia is in the right, that this is for the long haul, that "victory will be ours" - a fairly empty cry given that no one seems to have any suggestions for what victory might look like.
This visit will mean a great deal to the Ukrainian people. It will mean a very different thing to most Russians who will see the version of events that state TV feeds them.
It may also simply serve to strengthen Vladimir Putin's resolve in a fight he knows will go on for some considerable time.
The West has confounded sceptics with its staying power - but can it keep it up?
By Dominic Waghorn, international affairs editor
In war, pictures have great power. In the middle of a brutal, dark winter the leader of the free world has appeared by surprise in Kyiv.
They are extraordinary pictures, the US president on a sunny day strolling through the Ukrainian capital on a walkabout in his trademark aviator shades alongside President Zelenskyy in his military fatigues.
The sight brings hope and succour to the people of Ukraine but also sends a clear signal to allies, enemies, and doubters alike.
Joe Biden's message is that America is in it to the end. That is crucial because the longer this war goes on the greater the doubts about the West's ability to stand together and we are now entering a second year.
Ahead of this visit, President Biden's host in Warsaw, Polish President Andrzej Duda, told Sky News that Vladimir Putin is trying to exhaust the West. He has time and numbers on his side. There seems for now to be an unlimited resource of men he can feed the meatgrinder of his war machine.
He shows no compunction for their fate. And he is the dictator of an authoritarian state. Its people have so far remained quiescent about the senseless deaths of tens of thousands of young men.
Putin hopes still to divide the allies supporting Ukraine and tire them out. They are moving at different speeds. It took months for instance to agree to send modern battle tanks. There is still an unresolved debate about how much military aid can be given to Ukraine.
Everything they need to beat Russia soon, say the hawks. Others worry that a cornered humiliated Putin could resort to desperate means.
When Joe Biden is finished in Kyiv, he flies to Warsaw to meet allies for the diplomatic end of this trip. They have confounded the sceptics and maintained a far greater unity than many expected.
But can they keep it up? Can they show they have the staying power to outlast Russia as this war drags on past the grim milestone of this week's anniversary?
Biden's visit has a clear message for Putin
By Deborah Haynes, security and defence editor
History was made in Kyiv today with the first visit to Ukraine by US President Joe Biden almost one year on from a Russian invasion that was designed to topple the government.
In the ultimate snub to Russia's Vladimir Putin, the American leader met his Ukrainian counterpart, Volodymyr Zelenskyy, at the presidential palace before paying tribute to the many tens of thousands of Ukrainian military lives lost fighting to expel Russian invaders.
"Good morning, Mr President" was the greeting in English given by Mr Zelenskyy as Mr Biden emerged from a motorcade of vehicles that brought him to the capital in secrecy and under an unprecedented security lockdown.
Incredibly, Ukraine's president has greeted two different serving British prime ministers since Russian forces launched their full-scale war on 24 February last year.
But it is the first time the US president has chosen to make a journey that is not without risk.
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Kyiv is frequently the target of Russian drone and missile strikes, though Russia would surely want to avoid deliberately targeting the US president - a move that would be tantamount to a declaration of war against the United States.
Air raid sirens did go off as Mr Biden and Mr Zelenskyy visited a golden-domed monastery by a large square in the capital, where the husks of destroyed Russian tanks and other military vehicles form a display of defiance.
A memorial wall to the soldiers who have died fighting Russia's war, which began in 2014 with the annexation of Crimea but was significantly amplified last year with the all-out invasion, frames one side of the square outside St Michael's monastery.
The US president visited the memorial, where a US and a Ukrainian wreath were laid next to each other.
The symbolism of this trip is important, but so too is the substance.
Mr Biden wanted to make clear in his words and pledges, including new weapons and ammunition for Ukraine, that the United States would support Kyiv "for as long as it takes".
The US and its allies know that the Kremlin believes time is on Russia's side, suspecting the West will become distracted by other priorities or will fail to make the military investments necessary to keep supplying the Ukrainian military with the hardware it needs to fight.
By visiting Ukraine himself, with the risk that entails, the American president will be hoping he sends a clear message to Mr Putin that US support is here to stay.
Away from Kyiv, there are signs Russia has begun another offensive
From Alex Rossi, international correspondent, in Dnipro
Away from Kyiv, we are seeing definite signs that the Russians have begun their offensive in the east of Ukraine.
In recent days, there have been extremely violent clashes between Ukrainian and Russian forces around the city of Vuhledar in the Donetsk region.
Russian troops have been sending in human waves of infantry to try to seize Vuhledar - although the Ukrainian military say they have beaten back that assault, inflicting huge casualties on the Russians.
Meanwhile, Russian forces aided by the Wagner mercenary group have intensified their push to take the city of Bakhmut since seizing control of the neighbouring salt mining city of Soledar a month ago.
With Bakhmut encircled on three sides by Russian forces, there is now effectively only one road for the Ukrainians to take in and out of the city, and that route is being heavily shelled.
The Ukrainian forces now face a clear choice there - stand and fight, or retreat to save men and ammunition - an extremely difficult decision to be made while Kyiv too considers its own counter-offensive in the coming weeks and months.