Russian military commander Vadim Shishimarin, accused of killing a Ukrainian civilian in the Sumy region on Feb. 28, is set to go to trial on May 19, according to Ukraine's prosecutor general Iryna Venediktova.

The 21-year-old soldier allegedly fired his AK-47 at a car driven by a 62-year-old Ukrainian man, killing him at the scene, Venediktova said.

Shishmarin is charged with murder and two counts of robbery.

Prosecutor Andriy Syniuk said Shishmarin has cooperated throughout the investigation.

He is the first member of the Russian military to face charges, Venediktova said.

He could face a life sentence if convicted.

-ABC News' Nadine El-Bawab and Tatiana Rymarenko

On a Friday phone call with Swedish Prime Minister Magdalena Andersson and Finnish President Sauli Niinistö, President Joe Biden "underscored his support for NATO’s Open Door policy and for the right of Finland and Sweden to decide their own future, foreign policy, and security arrangements," according to the White House.

White House press secretary Jen Psaki said Thursday that the U.S. "would support" Finland and Sweden applying to join NATO "should they choose to apply."

Dmitry Polyanskiy, Russian deputy ambassador to the United Nations, told a British news podcast that Finland and Sweden officials "know the moment they become members of the NATO, it will imply certain mirror moves on the Russian side. … If there are NATO detachments in those territories, these territories would become a target -- or a possible target -- for a strike."

On Friday's call, Biden, Andersson and Niinistö "reiterated their shared commitment to continued coordination in support of Ukraine and the Ukrainian people affected by the war," according to the White House statement.

-ABC News' Molly Nagle

Secretary of Defense Lloyd Austin spoke to his Russian counterpart, Sergei Shoigu, for the first time since the invasion of Ukraine began, according to a statement from Pentagon press secretary John Kirby.

Austin urged for an immediate ceasefire and "emphasized the importance of maintaining lines of communication," the statement said.

-ABC News' Matt Seyler

Russian troops suffered "significant" loss while attempting to cross a river in the disputed Donbas region of war-torn eastern Ukraine, the U.K. Ministry of Defense said Friday in an intelligence update.

"Ukrainian forces successfully prevented an attempted Russian river crossing in the Donbas," the ministry said. "Images indicate that during the crossing of the Siverskyi Donets river west of Severodonetsk, Russia lost significant armoured manoeuvre elements of at least one Battalion Tactical Group as well as the deployed pontoon bridging equipment."

"Conducting river crossings in a contested environment is a highly risky manoeuvre and speaks to the pressure the Russian commanders are under to make progress in their operations in eastern Ukraine," the ministry added. "Russian forces have failed to make any significant advances despite concentrating forces in this area after withdrawing and redeploying units from the Kyiv and Chernihiv Oblasts."

On Wednesday, the Ukrainian Ministry of Defense released images purportedly showing a wrecked pontoon crossing over the Siverskyi Donets river, with a number of damaged or destroyed armored vehicles on both banks.

"Artillerymen of the 17th tank brigade of the #UAarmy have opened the holiday season for [Russian forces]," the ministry said in a post on Twitter, alongside the photos. "Some bathed in the Siverskyi Donets River, and some were burned by the May sun."

The Ukrainian Armed Forces' Strategic Communications Directorate also tweeted images of the scene, purportedly showing the smoking wreckage after artillery units and land forces "destroyed all attempts by the Russian occupiers to cross the Seversky Donets River."

White House national security advisor Jake Sullivan hinted Thursday of more sanctions coming against Russia in the "next week or two" aimed at targeting ways Moscow is evading sanctions already imposed.

“Where our focus will be over the course of the coming days is on evasion,” Sullivan said Thursday at the Economic Club of Washington. “As Russia tries to adjust to the fact that it’s under this massive economic pressure, what steps do they take to try to evade our sanctions and how do we crack down on that? And I think we'll have some announcements in the next week or two that identify targets that are trying to facilitate that evasion both inside Russia and beyond."

When Sullivan was asked whether sanctions will automatically be lifted if a negotiated peace deal between Russia and Ukraine is worked out, he appeared cautious with his words, saying, “a lot of that depends on what the shape and scope” of the agreement is.

“A lot of it depends on what the Ukrainians, in consultation with us and the Europeans come to agree to," Sullivan said. "You know, we're not going to do a deal over the head of the Ukrainians where we give a bunch of sanctions relief to Russia. But if some measure of sanctions relief were built in to some credible diplomatic solution led by the Ukrainians, that's something that we would happily discuss."

But Sullivan said Russian oligarchs shouldn't expect to ever get back their yachts and other assets seized under sanctions that have been imposed, saying the ultimate goal is "not to give them back” once the war is over.

“The president is actively looking at how we can deal with the fact that as we seize these assets, our goal is not to give them back. Our goal is to put them to a better use than that," Sullivan said. "But I'll be careful in what I say today because there's an ongoing kind of policy process around how we end up dealing with that question. But, rest assured, that the goal is not just to sit on them for a while."

-ABC News' Justin Gomez