Throwing America’s full weight behind the Nordic nations, President Joe Biden said he “strongly” backs their NATO bid and offered US support in the event of “aggression” during the application process.

In a sign of Washington’s resolve to stand firm with Ukraine, the United States reopened its embassy in Kyiv after a three-month closure, with employees raising the Stars and Stripes in a modest ceremony.

Biden’s comments came one day before he was to welcome Finnish President Sauli Niinisto and Swedish Prime Minister Magdalena Andersson to the White House for meetings set to underscore the strategic reach of their decision.

Reacting to the NATO applications, British Prime Minister Boris Johnson said they would not have been expected a short time ago, “but Putin’s appalling ambitions have transformed the geopolitical contours of our continent”.

The accession bid faces stiff 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 the Nordic nations to guard against any Russian aggression.

“We’re confident that at the end of the day Finland and Sweden” will enter NATO and “that Turkey’s concerns can be addressed,” US National Security Advisor Jake Sullivan said.

In an effort to lower the diplomatic heat, US Secretary of State Antony Blinken met at the United Nations Wednesday with Turkey’s Foreign Minister Mevlut Cavusoglu, who called the face-to-face discussion “extremely positive.”

‘Catastrophic mistakes’

On the ground, in Ukraine’s ruined port city of Mariupol more than 1,000 Ukrainian soldiers including senior commanders remained inside the besieged Azovstal steel plant, a pro-Russian separatist leader said.

Moscow said 959 of the troops had surrendered this week.

Kyiv’s defence ministry pledged to do “everything necessary” to rescue the personnel still in the sprawling plant’s tunnels but admitted there was no military option available.

Those who have left the heavily shelled Azovstal plant were taken into Russian captivity, including 80 who were seriously wounded, Russia’s 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 by international bodies.

Ukraine’s President Volodymyr Zelensky hit out at Moscow in his nightly address to the nation, calling Russia’s invasion an “absolute failure” and saying the once-mighty military has nearly exhausted its missile stockpile.

“They are afraid to acknowledge that catastrophic mistakes were made at the highest military and state level,” Zelensky said.

‘Clear signal’

In Ukraine’s first trial for war crimes—expected to be the first of many over the Russian invasion—Vadim Shishimarin, a shaven-headed sergeant from Irkutsk in Siberia, faces a life sentence after his guilty plea in a cramped Kyiv courtroom.

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.

“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”.

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.

Last-ditch resistance

The Kremlin meanwhile 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 like 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.

Meanwhile top EU officials urged member states to be ambitious in helping Ukraine rebuild after the war, including through possible joint borrowing to cover the massive costs.