A 21-year-old Russian soldier on Wednesday pleaded guilty to the cold-blooded murder of a Ukrainian civilian, as Kyiv began a judicial reckoning for alleged atrocities after nearly three months of war.
Ukraine's first trial for war crimes since Russia invaded on February 24 came as President Vladimir Putin was forced also to reckon with the prospect of NATO vastly expanding its reach on his borders.
Abandoning decades of non-alignment, Finland and Sweden formally submitted a joint application to join the military alliance at its headquarters in Brussels.
British Prime Minister Boris Johnson said the applications would not have been expected a short time ago, "but Putin's appalling ambitions have transformed the geopolitical contours of our continent".
The applications face resistance from NATO member Turkey, which accuses the Nordic neighbours of harbouring anti-Turkish extremists.
President Recep Tayyip Erdogan demanded "respect" from NATO over his government's concerns.
But Western allies remain optimistic they can overcome Turkey's objections. For now, several including Britain have offered security guarantees to Finland and Sweden to guard against any Russian aggression.
On the ground, in Ukraine's ruined port city of Mariupol, a unit of soldiers holding out in the Azovstal steelworks have already been bearing the brunt of Russia's aggression for weeks.
But Moscow said that 959 of the troops had surrendered this week.
Kyiv's defence ministry said it would do "everything necessary" to rescue the undisclosed number of personnel still in the sprawling plant's tunnels but admitted there was no military option available.
A pro-Russian separatist leader put the number of Ukrainian fighters still inside at more than 1,000.
"I can't imagine how they did it," said Maksym Malyovanyi, a 23-year-old set designer in Kyiv.
"As I see it, there are normal people, and then there's those guys," he told AFP.
Those who have left Azovstal were taken into Russian captivity, including 80 who were heavily wounded, the Russian defence ministry said.
The ministry, which published images showing soldiers on stretchers, said the injured were transported to a hospital in the eastern Donetsk region controlled by pro-Kremlin rebels.
The defence ministry in Kyiv said it was hoping for an "exchange procedure... to repatriate these Ukrainian heroes as quickly as possible".
But their fate was unclear, with Kremlin spokesman Dmitry Peskov refusing to say whether they would be treated as criminals or prisoners of war.
Putin had "guaranteed that they would be treated according to the relevant international laws", Peskov said.
Russia's alleged disregard for international law has played out in Ukraine with accusations -- including mass rape and massacres -- that are under investigation also by international bodies.
Vadim Shishimarin, a shaven-headed sergeant from Irkutsk in Siberia, is expected to be the first of many prosecuted by Ukraine itself. He faces a life sentence after his guilty plea in a cramped Kyiv courtroom.
"By this first trial, we are sending a clear signal that every perpetrator, every person who ordered or assisted in the commission of crimes in Ukraine shall not avoid responsibility," prosecutor general Iryna Venediktova said.
Russia's government has no information on the soldier, Peskov said, adding that many such cases reported by Ukraine are "simply fake or staged".
Shishimarin admitted to a war crime in shooting dead an unarmed 62-year-old man in Ukraine's Sumy region four days into the invasion, as the man rode a bicycle.
The International Criminal Court is deploying its largest-ever field team to Ukraine, with 42 investigators, forensic experts and support staff being sent into the field to gather evidence of alleged war crimes.
The US State Department also announced it was creating a special unit to research, document and publicise Russian war crimes.
But Russia says it is bent on eliminating a "Nazi" threat on its borders.
Peskov accused Kyiv of a "complete lack of will" towards peace talks, after Ukrainian negotiator Mykhaylo Podolyak said stop-start dialogue was "on hold", having failed to yield any breakthroughs.
'My war is not over'
The Kremlin also intensified a tit-for-tat round of diplomatic expulsions against European countries, ordering out dozens of personnel from France, Italy and Spain.
Despite their last-ditch resistance in places such as Mariupol, and their successful defence of Kyiv, Ukrainian forces are retreating across swathes of the eastern front.
White smoke from burning fields marks the pace of Russia's advance around the village of Sydorove, on the approaches to the militarily important city of Slovyansk and Ukraine's eastern administrative centre in Kramatorsk.
Army volunteer Yaroslava, 51, sat on a slab of concrete jutting out from the remains of a school in Sydorove where her husband's unit set up camp before it was hit by a Russian strike.
She stared at a spot where rescuers and de-miners had spotted a motionless hand reaching out from the rubble.
"We had settled in London before the war but felt like we had no choice but to come back," Yaroslava said.
"My two sons have just signed three-year contracts with the army. We will fight. We will still fight," she said without moving her eyes.
"My war is not over."