Ukrainian servicemen ride on a fighting vehicle outside Kyiv, Ukraine. As Russian forces pull back from Ukraine's capital region. Photo / AP
The past week may go down as the moment the Ukraine war began to turn against Russia.
Vladimir Putin's forces suffered a series of shocking reverses on the battlefield. For the first time, Ukraine recaptured more territory than it lost every day for an entire week, pushing Russian forces 32km back from Kyiv.
Russia's legendary 4th Guards Tank Division, storied for its victories at Stalingrad and Berlin, was routed in a small, little-known Ukrainian town called Trostyanets.
By the end of the week, Ukraine even appeared to take the war to Russia as Kyiv refused to confirm whether it was behind a cross-border helicopter raid that left an oil depot burning out of control in the Russian city of Belgorod.
In Russia, Putin seemed ever more isolated, amid claims from Western intelligence that he is being lied to by ministers and generals too scared to tell him the truth.
But there were warnings the most dangerous moments may lay ahead, as Ukrainian forces waited in First World War-style trenches for a new Russian onslaught on the Donbas, and Western capitals weighed up the risks of Putin turning to weapons of mass destruction.
The week's most stunning dispatches came from Trostyanets, a small town of some 20,000 people near Sumy in north-eastern Ukraine.
Pictures from the town last weekend showed the tanks of Russia's 4th Guards Kantemirovskaya division reduced to twisted and smoking wreckages.
The 4th Guards is so synonymous with Russian military prowess that a Moscow metro station is named after it.
It played a key role in two of the most momentous battles in modern history: the great Soviet defensive stand at Stalingrad, which turned back the Nazi advance at a cost of more than one million lives, and the Battle of Berlin when the Nazis were finally defeated.
Yet last weekend the legendary division was humbled by Ukraine in a shocking illustration of how badly the war is going for Russia.
The bad news kept coming for Moscow, as Ukraine pushed its forces 32km back from Kyiv.
On Wednesday, Ukraine clawed back the rubble that remains of the key suburb of Irpin, and on Thursday it recaptured Hostomel airport, which Russia seized at the start of the war when Moscow still believed it could take Kyiv in a matter of days.
It is Ukrainian tanks that are making history now, as the country's 1st Tank Brigade broke the Russian siege of Chernihiv in the north on Thursday.
Kyiv looks out of Putin's reach now. Even the much discussed 40-mile convoy of Russian armour that spent weeks waiting outside the city has dispersed, seemingly melted away in the fog of war.
The humiliation for Russia did not end there.
Ramzan Kadyrov, the Chechen leader who has been called "Putin's attack dog", was caught lying after he claimed he was in Ukraine.
Kadyrov posted a picture of himself praying to Mecca with a heavy machine gun at his side on social media and claimed it had been taken outside the besieged Ukrainian city of Mariupol. But the tell-tale logo of a Pulsar petrol station in the background gave him away: there are no Pulsar petrol stations in Ukraine, and the picture had been clearly taken in Russia.
Putin's government looks increasingly disarrayed, with senior commanders under house arrest and officials appearing to contradict each other.
Sergei Shoigu, Russia's defence minister, finally turned up on Tuesday, putting an end to speculation over his whereabouts after he disappeared from sight for two weeks.
Looking distinctly greyer than the last time he was seen in public, General Shoigu confirmed Russian forces were pulling back from Kyiv and the north to focus on the Donbas.
The move had already been announced by General Sergei Rudskoi of the general staff last week, but at the time it was contradicted by the Kremlin.
The return of General Shoigu appeared to suggest some form of internal struggle over strategy within Putin's government.
General Shoigu was the one member of his inner circle who appeared to have a personal relationship with Putin: the two were pictures on hunting and fishing holidays together in Siberia. But there are reports they have fallen out, amid claims from US intelligence this week that Putin is angry with his defence minister and feels he has been lied to about the war in Ukraine.
That was echoed by British intelligence, which said senior Russian officials are afraid to tell Putin the truth.
A source in US intelligence said this week: "We have information that Putin felt misled by the Russian military. There is now persistent tension between Putin and the ministry of defence, stemming from Putin's mistrust in the ministry of defence leadership."
Declassified intelligence claimed Putin "didn't even know his military was using and losing conscripts... showing a clear breakdown in the flow of accurate information".
Sir Jeremy Fleming, the head of GCHQ, said this week: "They are afraid to tell him the truth." But he added: "What's going on, and the extent of these misjudgments, must be crystal clear to the regime."
Fleming claimed Russian troops are so demoralised they are refusing to obey orders, sabotaging their own equipment and accidentally shooting down their own aircraft.
Unusual aircraft activity ahead of his appearance at a Moscow rally last week has fuelled speculation Putin may be spending most of his time in a nuclear bunker somewhere near the Urals, adding to his isolation.
Senior officials, including General Roman Gavrilov, deputy head of the National Guard, and General Sergei Beseda, head of foreign intelligence in the FSB - the Russian security service - have reportedly been sacked and are being held under house arrest.
On the ground in Ukraine, the withdrawal of Russian forces from Kyiv and the north appears to be genuine.
They continue to fire on civilian targets, including a cancer hospital in Chernihiv, and Ukrainian officials have warned the situation is still dangerous, but it is not unusual for armies to fire to cover a retreat.
Military situation in the Donbas
Attention is now shifting to the Donbas, where Russia says it will concentrate its military operations. Tens of thousands of battle-hardened Ukrainian troops are preparing to face them in First World War-style trenches, amid warnings the fighting could be brutal and drawn-out.
With both sides concentrating their forces on a single front, military experts say the war could drag on for three years or more.
Although Russia has sustained heavy casualties and is clearly losing the war, history warns Ukraine cannot afford to be complacent.
The USSR faced similar heavy losses and failed in its objective of taking control of Finland in the 1939-40 Winter War. But Finland still had to cede territory in Karelia to the Soviets before Stalin agreed to call off his troops.
There is an even starker warning from Stalingrad, where the legend of Russia's 4th Guards tank division was forged.
Stalingrad was the decisive turning point on the Eastern Front of the Second World War, as the Red Army turned back the German advance. But victory came at a harrowing cost of more than 1.1 million Soviet troops' lives — considerably more than the German losses.
The Soviets won on the Eastern front in part because Stalin was prepared to accept immense losses of his own forces. It remains to be seen whether far smaller losses will be enough to turn back Putin.
Meanwhile, the threat of nuclear escalation continues to hang over the continent. Dmitry Peskov, the Kremlin spokesman, attempted to play down the risk of Russia resorting to nuclear weapons for the second time in as many weeks.
"No one is thinking about even the idea of using nuclear weapons," Peskov told American television.
But he has been contradicted by other senior figures, notably Dmitry Medvedev, a former president and close ally of Putin, who has issued repeated warnings that Russia will use nuclear weapons if it is threatened.
And claims this week that Russian jets armed with nuclear bombs flew over Sweden earlier this month in a deliberate act of intimidation will do nothing to calm fears.
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