Russia-Ukraine updates: Putin suspends key US-Russia nuclear treaty in speech denouncing West

More clashes broke out Monday in Russia's Dagestan capital city, as police tried to disperse hundreds of protesters demonstrating against the Kremlin’s military mobilization of men to fight in Ukraine.

Videos circulating on social media showed scuffles between protesters and police in Makhachkala.

On Sunday, there were violent clashes in Dagestan, with police firing warning shots and people angrily shouting chants against the mobilization.

Russian President Vladimir Putin announced last week that he is mobilizing 300,000 more troops against Ukraine.

The announcement sparked major protests in Moscow and at least 30 other cities across Russia over the weekend. At least 17 military recruitment offices have been targeted with arson attacks. A man was detained by authorities on Monday after he allegedly opened fire on a recruitment center in Siberia, severely injuring a recruitment officer.

-ABC News' Patrick Reevell

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.

"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