Nato says between 7000 and 15,000 Russian soldiers have been killed in four weeks of fighting in Ukraine, where the country's defenders have put up stiffer-than-expected resistance and denied Moscow the lightning victory it hoped for.
A senior Nato military official said the estimate was based on information from Ukrainian officials, what Russia has released — intentionally or not — and intelligence gathered from open sources. The official spoke on condition of anonymity under ground rules set by Nato.
When Russia unleashed its invasion on February 24, a swift toppling of Ukraine's democratically elected government seemed likely. It has been Europe's biggest offensive since World War II and Russia brandished the prospect of nuclear escalation if the West intervened.
But with Wednesday marking four full weeks of fighting, Russia is bogged down in a grinding military campaign, with many dead, no immediate end in sight, and its economy crippled by Western sanctions. US President Joe Biden and key allies are meeting in Brussels and Warsaw this week to discuss possible new punitive measures and more military aid to Ukraine.
As Biden left the White House on Wednesday for the flight to Europe, he warned there is a "real threat" Russia could use chemical weapons and said he will discuss that danger with the other leaders.
The war's economic and geopolitical shockwaves — with soaring energy prices, fears for global food supplies, and Russia and China aligning in a new world order with Cold War echoes — have reverberated across a planet yet to emerge from the COVID-19 crisis.
In an apparent reflection of growing divisions in Russia's top echelons, top official Anatoly Chubais has resigned, Kremlin spokesman Dmitry Peskov told the Interfax news agency.
Chubais, the architect of Russia's post-Soviet privatization campaign, had served at a variety of top official jobs over three decades. His latest role was as Putin's envoy to international organizations.
Peskov would not say if Chubais had left the country.
With his olive-drab T-shirts, unshaven face and impassioned appeals to governments around the world, Ukrainian President Volodymyr Zelenskyy has been transformed into a wartime leader and Russian President Vladimir Putin's number one antagonist. Addressing Japan's parliament on Wednesday, Zelenskyy said four weeks of war have killed thousands, including at least 121 of Ukraine's children.
"Our people cannot even adequately bury their murdered relatives, friends and neighbours. They have to be buried right in the yards of destroyed buildings, next to the roads," he said.
Repeatedly pushed back by hit-and-run Ukrainian units armed with Western-supplied weapons, Russian troops are shelling targets from afar, falling back on tactics they used in reducing cities to ruins in Syria and Chechnya.
Major Russian objectives remain unfulfilled. The capital, Kyiv, has been shelled repeatedly hit but is not even encircled.
More shelling and gunfire shook the city Wednesday, with plumes of black smoke rising from the western outskirts, where the two sides battled for control of multiple suburbs. Mayor Vitali Klitschko said at least 264 civilians had been killed in the capital since war broke out.
In the south, the port city of Mariupol has seen the worst devastation of the war, under weeks of siege and bombardment. But Ukrainian forces have prevented its fall, thwarting an apparent bid by Moscow to fully secure a land bridge from Russia to Crimea, seized from Ukraine in 2014.
Zelenskyy said 100,000 civilians remain in a city that had 430,000 people. It has been shattered by strikes from air, land and sea, and repeated efforts to get desperately needed food and other supplies to those trapped have often failed.
'Deliberate terror': Russia accused of seizing relief workers
Zelenskyy has accused Russian forces of seizing 15 humanitarian workers on their way to provide essential aid for the decimated city of Mariupol, as evacuations and shelling continue into the four-week long conflict.
"Sadly, almost all of our efforts are sabotaged by Russian occupants, by [their] shelling or deliberate terror," he said.
"Today, one of the humanitarian convoys was seized by occupants on an arranged route near Mangush.
"Employees of the State Emergency Service and bus drivers have been taken captive. We are doing everything to set our people free and unblocked the movement of humanitarian cargo."
Nearly 100,000 people are reported to be trapped inside the ruins of Mariupol. The besieged port city has faced weeks of bombing and shelling from Russian forces, while being cut off from water, electricity, food and medication.
The conditions are so poor, they've been described by the Human Rights Watch as a "freezing hellscape riddled with dead bodies and destroyed buildings".
While Ukraine President Volodymyr Zelenskyy estimates 7026 have been able to escape the city, several attempts to create humanitarian corridors and evacuations have previously been sabotaged by Russian attacks.
On the President's Tuesday nightly address (local time), Zelenskyy said the remaining residents were living in "inhumane conditions," with Russian troops instilling "deliberate terror" on those attempting to flee.
Earlier in the day, Zelenskyy issued a grim plea to the Kremlin where he urged Russia to allow civilians to evacuate Mariupol.
"There is nothing left there. Only ruins," said Zelenskyy in a video-link up with the Italian parliament.
Reports from Tuesday morning also suggested that Russian soldiers have begun entering the city.
This comes as the city was rocked by two "super powerful bombs" on Wednesday morning, however the death toll as a result of the attack has yet to be revealed.
'Unwinnable:' Grim prediction for Russia's war effort
The United Nations has declared Russia's war on Ukraine "unwinnable", imploring its government to begin peace talks.
"Sooner or later, it will have to move from the battlefield to the peace table. This is inevitable," said Secretary-General of the United Nations, António Guterres, addressing journalists outside the Security Council.
"The only question is: How many more lives must be lost?
"How many more bombs must fall? How many more Mariupols must be destroyed? How many more Ukrainians and Russians will be killed before everyone realises that this war has no winners – only losers?"
Meanwhile, Ukrainian and US sources have said that Russia's military efforts have been greatly depleted.
In a press briefing with the US Department of Defence, a senior official places Russia's combat power at "just below 90 per cent".
They did however, explain that while they're "expending an awful lot" during combat, they also have "a lot available to them".
"We recognise they are taking casualties every day," said the official.
"They are losing aircraft. They are losing armour and vehicles, no doubt about that.
"We do see them continue to suffer casualties and losses, but they had – they built up an awful lot of combat power."
Today, a report from the Ukrainian military claimed Russian forces have a mere three days worth of food, ammunition and fuel left.
Pentagon officials agreed that Russian forces are "struggling on many fronts," and that several isolated units have reported supply issues, The Guardian reports.
"It is consistent with an advance which has ground to a halt. Failures in the logistic chain has been one of the reasons they have not been as effective as they hoped," they wrote.
The Defence Intelligence of Ukraine also claimed that Russia had resorted to "hidden mobilisation" tactics, accusing the Russian Prosecutor's Office of offering to release all credit obligations from people who sign a contract with the army. Similar proposals have also been given to criminals in exchange for full amnesty.
"Given the total failure to replenish the military reserve, the occupiers are moving to new forms of hidden 'mobilisation,'" a spokesman wrote via their Facebook.
'Existential threat:' Russia refuses to deny use of nuclear weapons
In a bold declaration, Vladimir Putin's press secretary refused to quash the potential for nuclear weapons to be used in Russia's assault on Ukraine.
CNN reports Dmitry Peskov repeatedly denied ruling out the possibility of a nuclear attack in order to achieve Russia's military goals.
"If it is an existential threat for our country, then it can be," Peskov told CNN's chief international correspondent Christiane Amanpour.
Peskov doubled down on Russia's goals to "demilitarise" Ukraine and accused the government of being "nationalist battalions".
When asked about how Russia was progressing in the conflict, Peskov vaguely hinted Putin "hasn't achieved" his goals to date but said it was "going on strictly in accordance with the plans and the purposes that were established beforehand".
A Russian plot to assassinate Zelenskyy involving a "25-man death squad" has been foiled with the entire group arrested near the Slovakian border, it's been reported.
However, it's the manner in which the group's actions were uncovered which has raised eyebrows.
The hitmen were reportedly betrayed by their own side with elements within the Russian secret service, the FSB, informing Kyiv of their location and plans.
It's thought to be just one in a string of assassination attempts against senior members of the Ukrainian Government which have failed.
German newspaper Bild reported the group of 25 trained killers, led by a Russian secret service agent, were captured in the western Ukraine city of Uzhhorod on their way to the capital.
Uzhhorod lies close to the borders of both Slovakia and Hungary.
As well as an attack on Zelenskyy, the group were also planning "acts of sabotage" in the government district of Kyiv, it was alleged.
Their plan was to pretend to be members of Ukraine's territorial units to gain access to the city.
But news agency Unian said a faction with the Russian government against the invasion contacted Kyiv informing them of the plot, dooming the mission to failure.
"There is said to be a group of opponents of the war in the FSB which specifically gave information to the Ukrainians," stated Bild.
It's thought Moscow has enlisted the help of special forces from the restive Russian region of Chechnya as well as notorious soldiers-for-hire group Wagner to target the Ukrainian presidents.
In early March it was revealed there were more than a dozen assassination attempts against Zelenskyy in the first two weeks of the war alone.
"We have a very powerful network of intelligence and counterintelligence – they track it all," presidential adviser Mikhail Podolyak told the outlet Ukrainian Pravda.
Thwarted attempts by infiltrators have included would-be assassins who have been "liquidated" while attempting to get to Zelenskyy's government quarters, he said.