A veteran videographer and a 24-year-old Ukrainian journalist working for Fox News were both killed when their vehicle came under fire outside of Kyiv, the network said on Tuesday.

Pierre Zakrzewski, 55, and Oleksandra "Sasha" Kuvshynova were traveling Monday in Horenka with Fox News reporter Benjamin Hall, who remains hospitalized.

"Today is a heartbreaking day for Fox News Media and for all journalists risking their lives to deliver the news," the network's CEO, Suzanne Scott. said in a staff memo.

On Sunday, documentary filmmaker Brent Renaud, another veteran of covering war zones, died when Russian forces opened fire on his vehicle in Irpin, also outside of Kyiv.

The death of three journalists in a short span underscores the dangers faced by people chronicling the war in Ukraine, even those with extensive experience reporting from conflict zones.

The dangers for journalists seem to be increasing by the day, as the fighting seems to get more brutal and concentrated in more urban areas, said Summer Lopez, director of the Free Expressions Program at PEN America.

Zakrzewski, an Irish citizen who was based in London, had covered conflicts in Iraq, Afghanistan and Syria for Fox and won an internal "unsung hero" award for playing a key role last year in getting Fox's freelancers and their families out of Afghanistan after the U.S. withdrawal. He had been working in Ukraine since February.

"Such a fine man," tweeted Fox national security reporter Jennifer Griffin.

Trey Yingst, another colleague who worked with Zakrzewski in Ukraine, called him "as good as they come."

Kuvshynova was a local "fixer," as is known in war zones. She helped Fox crews navigate the Kyiv area, gathered information and spoke to sources. She had a passion for music, the arts and photography, Scott said in the staff memo.

"Several of our correspondents and producers spent long days with her reporting the news and got to know her personally, describing her as hard-working, funny, kind and brave," Scott wrote. "Her dream was to connect people around the world and tell their stories and she fulfilled that through her journalism."

In Washington on Tuesday, the Ukrainian ambassador to the United States, Oksana Markarova, thanked reporters who are on the ground in Ukraine.

"Risking their lives to tell the world the truth" is something that Ukraine and the world desperately need, she said at the National Press Club.

Jane Ferguson, a PBS "NewsHour" correspondent in Ukraine who has also reported from Afghanistan, Iraq, Somalia and Syria, said on Twitter that the war "is incredibly tough to cover as a field reporter, unlike any I have seen or experienced before."

With intense artillery fire that can reach for miles and a vague fluidity of army positions, there is really no front line, Ferguson wrote.

Ferguson said she and her crew were recently pulled out of their car at gunpoint by Ukrainian soldiers who mistakenly thought they were being filmed from the car. The journalists were waved on after their credentials were checked, "but for a few minutes it was pretty nasty."

There are few journalists officially embedded with troops - as they were in Iraq and Afghanistan, for example - so many reporters are driving around independently, and without good intelligence, which is particularly dangerous, Ferguson said.

In an interview, ABC News reporter Martha Raddatz said Ukraine reminded her of covering the siege of Sarajevo because there are no U.S. troops there.

"That is a huge thing for me," she said. "You realize, 'Oh, wait. There are no Americans here. There's no protection for us here.' I think you're very cognizant of that."

Gulnoza Said, coordinator of the Europe and Central Asia Program for the Committee to Protect Journalists, has been hearing from journalists in Ukraine concerned about checkpoints where it isn't clear if they're coming upon Russian or Ukrainian soldiers.

She said journalists are telling her they are worried that Ukrainian authorities may be seeking to limit the areas and hours in which they can work.

"I need to find out exactly what they want to do," she said. "I hope it is not because they want to control the narrative of the war."

News of Zakrzewski's death hit particularly hard Tuesday in Ireland. Irish premier Micheal Martin said he was deeply disturbed by the news.

"My thoughts are with their families, friends and fellow journalists," Martin said. "We condemn this indiscriminate and immoral war by Russia on Ukraine."

From The Associated Press