KYIV, Ukraine (AP) - The award-winning film “20 Days in Mariupol” made its premiere in Ukraine on Saturday, seen for the first time by some of the Ukrainian medics and first responders who were chronicled in the documentary about how Russian forces bombed and blasted their way into the southeastern port city last year.

Repeated standing ovations in a packed Kyiv cinema, mixed with tears and hugs, greeted those Ukrainian civil servants who toiled nearly non-stop in and around a Mariupol hospital that was a centerpiece of the film about the city early on in Russia's full-scale invasion of Ukraine on Feb. 24, 2022.

For some, the screening served as an unsettling flashback to their own brush with death in the city - a fate inescapable for untold numbers of other victims of Russia's invasion, including toddlers, infants and expectant mothers whose final moments were caught on video shown in the film.

“It was very hard emotionally because it reminded me of when we were leaving Mariupol, there were still a lot of casualties,” said Serhii Chornobrivets, 25, an ambulance worker who treated countless patients in the city, and is now a military medic. “I could have saved more people, but I didn't.”

“Watching that movie brought all those feelings back,” he added.

Many viewers the documentary, a joint project between The Associated Press and PBS Frontline, expressed their gratitude that the footage eventually got out to the world for history's sake.

The documentary by Associated Press journalist Mstyslav Chernov was built on some 30 hours of film from reporting along with AP photographer Evgeniy Maloletka and AP producer Vasilisa Stepanenko about the earliest phase of the Russian invasion of Mariupol.

They were the three international journalists to hold out longest in Mariupol during the Russian siege, serving as the world's eyes and ears amid the horrors of the onslaught. Their work along with Paris-based colleague Lori Hinnant won the prestigious Pulitzer Prize award for public service for the AP in May.

As communications networks collapsed and Russian forces closed in, it was never certain the footage would get out. Some was sent in snippets by mobile phone, the rest carried out in the journalists' final flight from the city.

“After this material was published, the entire world started helping us - as the real fighters that we are,” said Volodymyr Nikulin, a Mariupol police officer and a standout of the documentary for his cool-headed determination that word of the devastation reach a global audience. “Already this movie has become part of our history.”

The 94-minute film has received numerous award, including at the Cinema for Peace competition, the Cleveland International Film Festival, and at the Sundance Film Festival in January, where it had its world premiere. A wider opening in U.S. theaters begins next month.

“I hope it gives voice to all Ukrainians,” said Chernov, expressing his hope that it could help pave the way for international justice and accountability. “It's painful to think how small this piece really is ... those 20 days are a tiny fraction of all the tragedies that happened” in many parts of Ukraine.