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Sen. Steve Daines, R-Mont., became the first U.S. senator to visit Ukraine amid the Russian invasion, touring the mass graves in the city of Bucha and reporting "indisputable evidence of Putin's war crimes." He traveled with Rep. Victoria Spartz, R-Ind., who was herself born in Ukraine.

"While meeting with leaders in NATO countries bordering Ukraine, I was invited to meet Ukrainian officials in Kyiv and Bucha and see firsthand the butchery and war crimes committed by Putin," Daines said in a statement. "There is indisputable evidence of Putin’s war crimes everywhere—the images of shallow mass graves filled with civilians, women and children are heart-wrenching."

Daines told Fox News' "Your World with Neil Cavuto" on Thursday, "I've seen a lot of horrific things over the years in terms of storm damages and accidents. I've never seen anything like this. I mean, these were children. These were children who were murdered."

He went on: "It's atrocities. It's war crimes… there's an irrefutable case being made right now for the war crimes of Vladimir Putin and the soldiers who committed them."

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Sen. Steve Daines speaks with investigators in the Ukrainian city of Bucha. (Image courtesy of the office of Sen. Steve Daines.)

Daines concluded in his statement that Ukrainian President Volodymyr Zelenskyy "has been urging leaders from around the world to come to Ukraine—I’m proud to help show that America stands shoulder to shoulder with the people of Ukraine in their fight for freedom," the senator concluded.

Daines' office released photos and videos of the senator's visit to the war-ravaged cities of Bucha and Makariv. In Makariv, the senator found a child's wooden toy in the rubble.

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Steve Daines picks up a child's wooden toy found near the mass graves in Makariv. (Image courtesy of the office of Sen. Steve Daines.)

Hours after Daines' trip, White House Press Secretary Jen Psaki said that the White House was not considering sending President Biden to Ukraine. 

"No, we are not sending the president to Ukraine," she told Pod Save America.

Earlier this month, Ukrainian President Volodymyr Zelenskyy announced that his government had launched an investigation into alleged Russian atrocities in the area around the capital city of Kyiv, from which Russian forces had recently withdrawn.

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"We have just begun an investigation into all that the occupiers have done," the president added. "At present, there is information about more than three hundred people killed and tortured in Bucha alone. It is likely that the list of victims will be much larger when the whole city is checked. And this is only one city. One of the many Ukrainian communities that the Russian military managed to seize."

Russian Foreign Minister Sergei Lavrov accused Kyiv of setting up a "stage-managed anti-Russian provocation."

WARNING: GRAPHIC IMAGES

Associated Press journalists saw the bodies of at least 21 people in various spots around Bucha, northwest of the capital. One group of nine, all in civilian clothes, were scattered around a site that residents said Russian troops used as a base. They appeared to have been killed at close range. At least two had their hands tied behind their backs, one was shot in the head, and another's legs were bound. 

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"You saw what happened in Bucha," Biden said, describing Putin as both "brutal" and a "war criminal." "What’s happening in Bucha is outrageous and everyone sees it."

Ukraine's ambassador to the United Nations detailed shocking claims that Russian soldiers raped and abducted women and girls.