U.S. says credible reports indicate Russians executed surrendering Ukrainians

• Specifically, "the prohibition against the summary execution of civilians and combatants who are hors de combat by virtue of surrender, injury, or other forms of incapacitation," she said.
• Van Schaack added that the U.S. also has "credible reports of individuals killed execution-style with their hands bound; bodies showing signs of torture; horrific accounts of sexual violence against women and girls."

The bottom line: "These images and reports suggest that atrocities are not the result of rogue units or individuals; they, rather, reveal a deeply disturbing pattern of systematic abuse across all areas where Russia’s forces are engaged," Van Schaack said.

The big picture: The International Criminal Court and others are investigating whether Russian forces have committed war crimes and other human rights violations in Ukraine.

• President Biden accused Putin's forces earlier this month of committing "genocide" in Ukraine, but the Kremlin has repeatedly denied that its forces have committed any war crimes in the country.
• The Kremlin has repeatedly denied that its military has committed any atrocities in Ukraine.

Between the lines: War crimes have been historically hard to investigate and often even more challenging to prosecute, per Axios' Laurin-Whitney Gottbrath.

Go deeper: What counts as a war crime and why they're so hard to prosecute