National security adviser Jake Sullivan told ABC's "This Week" Sunday that U.S. intelligence indicated "there was a plan from the highest levels of the Russian government" for its forces to commit atrocities in Ukraine.

What he's saying: "The images that we've seen out of Bucha and other cities have been tragic, they've been horrifying, they've been downright shocking, but they have not been surprising," Sullivan told ABC's Jonathan Karl.

• "We, in fact, before the war began, declassified intelligence and presented it indicating that there was a plan from the highest levels of the Russian government to target civilians who oppose the invasion, to cause violence against them," Sullivan continued.
• "To organize efforts to brutalize them in order to try to terrorize the population and subjugate it. So this is something that was planned."

The big picture: The International Criminal Court last month launched an investigation into allegations of war crimes, crimes against humanity and genocide committed in Ukraine, charges the Kremlin has denied.

• Ukrainian prosecutors have opened some 5,600 cases of alleged war crimes since the beginning of the Russian invasion.
• President Biden said last week that Russian President Vladimir Putin should face a war crimes trial for the alleged massacre of civilians by Russian forces in the Kyiv region city of Bucha.

Worth noting: Jeremy Fleming, the head of British intelligence agency GCHQ, said last week that Putin's "Plan B has been more barbarity against civilians and cities."

• Sullivan noted to Karl that "individual soldiers or individual units got frustrated because the Ukrainians were beating them back" and they'd been "told they were going to have a glorious victory and just ride into Kyiv without any opposition with the Ukrainians welcoming them."
• "And when that didn't happen, I do think some of these units engaged in these acts of brutality, these atrocities, these war crimes even without direction from above," he added.

The bottom line: "I do think some of these units engaged in these acts of brutality, these atrocities, these war crimes, even without direction from above," Sullivan said.

• "But make no mistake, the larger issue of broad-scale war crimes and atrocities in Ukraine lies at the feet of the Kremlin and lies at the feet of the Russian president."

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