U.S. Secretary of State Antony Blinken announced Monday that the U.S. will give Ukraine another $457.5 million in civilian security assistance to bolster the efforts of Ukrainian law enforcement and criminal justice agencies "to improve their operational capacity and save lives.”

Blinken said some of the funds will also go toward supporting efforts to “document, investigate, and prosecute atrocities perpetrated by Russia's forces.” He said that since December, the United States has pledged more than $645 million toward supporting Ukrainian law enforcement.

Blinken's announcement follows a U.N.-led investigation that found Russian troops had committed war crimes in occupied areas of Ukraine, including the rape, torture and imprisonment of children.

-ABC News' Shannon Crawford

In a new interview, Ukrainian first lady Olena Zelenka told ABC News that recent developments in the war are upsetting, saying this is not an "easy period" for the people of Ukraine.

"When the whole world wants this war to be over, they continue to recruit soldiers for their army," said Zelenska, referring to Russian President Vladimir Putin's announcement last week that he is mobilizing 300,000 more troops against Ukraine. "Of course, we are concerned about this. We are worried and this is a bad sign for the whole world."

Zelenska, who spoke with ABC News' Amy Robach through a translator, said Ukrainians will continue to persevere in the face of conflict.

"The main difference between our army and the Russian army is that we really know what we are fighting for," she said.

Zelenska attended the United Nations General Assembly in-person in New York City, where she spoke to ABC News about the U.N.'s recent finding that war crimes have been committed in Ukraine by Russian troops. A .N.-appointed panel of independent legal experts reported that Russian soldiers have "raped, tortured, and unlawfully confined" children in Ukraine, among other crimes.

"On the one hand, it's horrible news, but it's the news that we knew about already," she said. "On the other hand, it's great news that the whole world can finally see that this is a heinous crime, that this war is against humanity and humankind."

A man has opened fire at a military enlistment office in eastern Russia, severely injuring a recruitment officer there.

An apparent video of the shooting was circulating online, showing a man shooting the officer at a podium in the officer in the city of Irkutsk.

Irkutsk’s regional governor confirmed the shooting, naming the officer injured as Alexander V. Yeliseyev and saying he is in intensive care in a critical condition.

The alleged shooter has been detained, according to the governor.

-ABC News’ Patrick Reevell

The Russian Defense Ministry announced a high-level shake-up in its military leadership amid reports Russian forces are struggling in the war against Ukraine.

The defense ministry said Saturday that Col. Gen. Mikhail Y. Mizintsev has been promoted to deputy defense minister overseeing logistics, replacing four-star Gen. Dmitri V. Bulgakov, 67, who had held the post since 2008.

Bulgakov was relieved of his position and is expected to be transferred "to another job,” the Defense Ministry statement said.

The New York Times reported that Mizintsev -- whom Western officials dubbed the “butcher of Mariupol" after alleged atrocities against civilians surfaced in the Ukrainian city in March, previously served as chief of Russia’s National Defense Management Center, which oversees military operations and planning.

In this previous role, Mizintsev became one of the public faces of the war in Ukraine, informing the public about what the Kremlin still calls a “special military operation.”

Mizintsev was put on international sanctions lists and accused of atrocities for his role in the brutal siege of the Mariupol.