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An American journalist and documentary filmmaker has been shot dead in Ukraine, said Andrew Nebytov, head of the National Police in Kyiv region.
Brent Renaud, 51, died in the Kyiv suburb of Irpin on Sunday in an attack that wounded another journalist.
Ukrainian authorities are thought to be trying to extricate the injured reporter from the combat zone.
Photos of Renaud's bloodied body appeared on social media. He had been travelling in a van with a group of journalists in Irpin when Russian troops opened fire.
Mr Nebytov said Renaud had “paid with his life” for going to Ukraine to shine a light on Russia’s “ingenuity, cruelty and ruthlessness”.
Jake Sullivan, the National Security Adviser to US President Joe Biden, said there would be "appropriate consequences" after the "shocking and horrifying" incident.
"This is part and parcel of what has been the brazen aggression on the part of the Russians where they have targeted civilians, they have targeted hospitals, they have targeted places of worship and they have targeted journalists," he told NBC's Face the Nation.
Renaud was working for Time Studios on a project about global refugee issues, the media outlet said.
"We are devastated by the loss of Brent Renaud," Time editor in chief Edward Felsenthal said.
"Our hearts are with all of Brent's loved ones. It is essential that journalists are able to safely cover this ongoing invasion and humanitarian crisis in Ukraine."
Danylo Shapovalov, a surgeon volunteering for the Ukrainian territorial defence, told AFP that the injured journalist was also a US citizen. He said Renaud had died instantly and he had treated the other victim.
Jane Ferguson, a correspondent for PBS Newshour, said she had stumbled upon the scene after Renaud was killed and saw his body covered in a blanket.
“Just left roadside spot near Irpin where body of American journalist Brent Renaud lay under a blanket,” she tweeted. “Ukrainian medics could do nothing to help him by that stage. Outraged Ukrainian police officer: 'Tell America, tell the world, what they did to a journalist.'”
"Today, a US journalist was killed in Ukraine," said French President Emmanuel Macron.
"Before him, others have been targeted, murdered, injured or kidnapped. Our thoughts are with all those journalists driven by courage and an ideal: the freedom to inform. This freedom is fundamental to our democracies."
Another US journalist who survived the attack spoke from his hospital bed to a reporter from Italian newspaper Internazionale.
Juan Arredondo said Renaud had been shot in the neck and his body “had to be left behind".
Mr Arredondo said the journalists were attacked when their vehicle was stopped at a Russian checkpoint.
“We had crossed the first bridge in Irpin. We were going to film other refugees leaving and we got into a car. Somebody offered to take us to the other bridge,” he said.
“We crossed a checkpoint and they started shooting at us. The driver turned around, there were two of us. My friend is Brent Renaud. He has been shot and left behind. I saw he has been shot in the neck. We got split.”
Renaud was carrying a press badge with the name of The New York Times. A representative said he had worked for it in the past but was not in Ukraine on assignment for the newspaper.
“We are deeply saddened to hear of Brent Renaud's death. Brent was a talented photographer and filmmaker who contributed to The New York Times over the years,” the newspaper said.
Myroslava Gongadze, a Ukrainian journalist living in the US, said Renaud had been her classmate when the two were studying under Harvard’s Nieman programme.
She described him as a “brave, sensitive and smart” journalist and said news of his death was “devastating”.
“His stories in our writing class made us cry,” she said.