U.S. is collecting evidence of possible Russian war crimes in Ukraine

EDITOR'S NOTE: This article contains a graphic photo of soldiers removing human remains.

The United States is collecting evidence of possible war crimes, human rights abuses and violations of international law by Russia during its ongoing invasion of Ukraine, a National Security Council spokesperson told NBC News on Monday.

The statement comes as Russia has been widely condemned for its attack on Ukraine, which has included shelling of civilian areas that has driven more than 1.5 million refugees out of the country.

It also comes a day after a New York Times journalist and the mayor of Irpin, Ukraine, reported seeing a family of two adults and two young children killed by Russian artillery, images of which were widely circulated around the world.

"We are appalled by Russia's brutal tactics and the rising number of innocent civilians who have been killed in Russian strikes, which have reportedly hit schools, hospitals, kindergartens, an orphanage, residential buildings and those fleeing through humanitarian corridors," the NSC spokesperson told NBC News.

"We are collecting evidence of possible war crimes, human rights abuses and violations of international humanitarian law," they said. "We support accountability using every tool available, including criminal prosecutions where appropriate."

The U.S. ambassador to the Organization for Security and Co-operation in Europe, Michael Carpenter, earlier Monday condemned Russian President Vladimir Putin for his "unprovoked war."

Carpenter said 45 participating states launched the so-called Moscow Mechanism to document and gather evidence of violations of international law. A report from that inquiry will be presented to the International Criminal Court and the International Court of Justice "so individuals at all levels are held to account," he said.

"The brutality of this war is both revolting and heartbreaking," said Carpenter. "Children have been killed, grandparents driven from their homes, families forced to flee their country in the face of relentless strikes on civilian infrastructure."

"The depravity of it all is mind-blowing."

Carpenter cited Russia's agreement on Saturday and Sunday to open a humanitarian corridor out of the cities of Volnovakha and Mariupol, which it then bombed as civilians began using it to flee the country.

"It is pure evil," he said.

The ambassador also noted that on Monday, Russia proposed that Ukrainians flee the areas under Russian attack by going to Russia and Belarus, which are allies.

"This is the height of cynicism," Carpenter said.

Secretary of State Antony Blinken told CNN on Sunday: "We've seen very credible reports of deliberate attacks on civilians, which would constitute a war crime. We've seen very credible reports about the use of certain weapons."

The International Criminal Court's chief prosecutor last week opened an investigation into Russia's conduct in Ukraine.

"I am satisfied that there is a reasonable basis to believe that both alleged war crimes and crimes against humanity have been committed in Ukraine in relation to the events already assessed during the preliminary examination by the Office," said the prosecutor, Karim Khan.