U.S. Secretary of State Antony Blinken announced Wednesday that the U.S. is officially resuming operations at its embassy in Kyiv.

"The Ukrainian people, with our security assistance, have defended their homeland in the face of Russia’s unconscionable invasion, and, as a result, the Stars and Stripes are flying over the Embassy once again," Blinken said in a statement.

The U.S. has put in place additional measures to increase the safety for its staff and enhanced its security measures and protocols.

"We are committed to confronting the challenges ahead," Blinken said. "We reaffirm our commitment to the people and government of Ukraine, and we look forward to carrying out our mission from the U.S. Embassy in Kyiv."

Finland and Sweden formally submitted their applications to join NATO to Secretary General Jens Stoltenberg Wednesday morning at the alliance’s Brussels headquarters.

Stoltenberg welcomed the requests, saying, "This is a good day, at a critical moment for our security," according to NATO.

"Every nation has the right to choose its own path. You have both made your choice, after thorough democratic processes. And I warmly welcome the requests by Finland and Sweden to join NATO," Stoltenberg said Wednesday.

Adding, "You are our closest partners. And your membership in NATO would increase our shared security."

Russian Sgt. Vadim Shyshimarin pleaded guilty Wednesday to shooting a 62-year-old Ukrainian man on Feb. 28. The guilty plea carries a life sentence.

It's the first trial Ukraine has conducted for an act that could be considered a war crime.

Asked by the presiding judge whether he accepted his guilt, Shyshimarin said: "Yes. Fully yes."

Kremlin spokesman Dmitri Peskov dismissed the proceedings on Wednesday, telling reporters that accusations leveled against Russian soldiers by Ukraine were "simply fake or staged."

-ABC News' Joe Simonetti

As Turkey becomes more vocal about its opposition to Sweden and Finland joining NATO, the State Department said it is still assured of the alliance's unified support for the two prospective members.

State Department spokesperson Ned Price said during a briefing Tuesday that Secretary of State Antony Blinken came away from meetings with NATO allies with a "sense of confidence there was strong consensus for admitting Finland and Sweden into the alliance if they so choose to join, and we're confident we'll be able to preserve that consensus."

Price said that assessment came from what Blinken heard in conversations behind closed doors.

Turkey's president, Recep Tayyip Erdogan, has publicly said that both candidates are untrustworthy because he perceives them as being supportive of groups Ankara views as extremist.

There is speculation that Turkey’s opposition is an attempt to leverage the moment to achieve its own policy goals or concessions from the U.S. Price said Tuesday that Turkey has not made any specific requests.

Price confirmed that Blinken will meet with his Turkish counterpart on the sidelines of the U.N. on Wednesday, adding that "other conversations are ongoing between and among current NATO allies and potential aspirant countries."

-ABC News' Shannon Crawford

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