AMSTERDAM (AP) — As an off-duty policeman who had just assassinated Russia's ambassador to Turkey stood in front of Burhan Ozbilici waving a gun, the veteran Associated Press photographer summoned the composure to stand his ground and keep taking pictures.

"I immediately decided to do my job because I could be wounded, maybe die, but at least I have to represent good journalism," Ozbilici said Monday as his image of gunman Mevlut Mert Altintas looming over the body of Ambassador Andrei Karlov was named World Press Photo of the Year.

Ozbilici's image of a political murder's immediate aftermath was part of a series titled "An Assassination in Turkey" that also won the Spot News - Stories category in the prestigious awards. The photos were captured in the moments before and after Altintas drew a handgun and shot Karlov at an Ankara gallery on Dec. 19.

"Burhan's striking image was the result of skill and experience, composure under extreme pressure and the dedication and sense of mission that mark AP journalists worldwide," AP Executive Editor Sally Buzbee said. "We are enormously proud of his accomplishment."

In the winning photo, the assassin, wearing a suit and tie, stands defiantly, pistol in his right hand pointed at the ground and with his left hand raised, his index finger pointing upward. His mouth is wide open as he shouts angrily. The ambassador's body lies on the floor just behind Altintas.

Pacing near the body of his victim, the gunman appeared to condemn Russia's military role in Syria, shouting: "Don't forget Aleppo! Don't forget Syria!" Altintas, who was a policeman, was later killed in a shootout with Turkish police.

Ozbilici said his professional instincts kicked in despite the shocking scene unfolding in front of him.

Explaining how he remained collected enough to keep taking pictures, he said: "I understood that this was big history, it was history, (a) very, very important incident."

The winning image announced Monday was among 80,408 photos submitted to the prestigious competition by 5,034 photographers from 125 countries. The World Press jury awarded prizes in eight categories to 45 photographers from 25 countries.

Jury chairman Stuart Franklin called Ozbilici's image "an incredibly hard-hitting news photograph" and part of a strong series documenting the assassination.

"I think Burhan was incredibly courageous and had extraordinary composure in being able to sort of calm himself down in the middle of the fray and take the commanding pictures that he took," Franklin said. "I think as a spot news story it was terrific."

But Franklin said after the presentation that he did not vote for Ozbilici's photo to win the overall prize, despite the quality of the image and the bravery involved in capturing it.

He said he had a philosophical issue with recognizing as the world's top photograph a picture showing the victim and shooter in the same frame because he thinks it gives the shooter the publicity he sought by carrying out the shooting as he did.

Buzbee said the AP considers Ozbilici's image a rare, unscripted insight into one of the world's most intractable problems, that of violent extremism, and thus the opposite of propaganda, which the news agency refrains from publishing.

Denis Paquin, AP's acting director of photography, said Ozbilici's actions that day were typical of his professionalism.

"Burhan would tell you he was just doing his job. His humble professionalism, combined with incredible courage, enabled him to capture these unforgettable images," Paquin said.

Ozbilici said that while he kept his camera trained on the gunman, he felt as if journalists around the world were saying, "Hey man, you are representing all of us. Don't go away! Stand! We are supporting you, we are praying for you."

The eclectic selection of winners in the photo competition's eight categories highlighted the dominant news topics of the last year — including conflict in Syria and Iraq, Europe's migrant crisis, the death of longtime Cuban leader Fidel Castro and the Olympic Games in Rio.

Winning nature photos included images depicting humanity's devastating effect on wildlife, such as a gruesome photograph of a poached rhino with its horn hacked off and another showing a turtle swimming while enmeshed in a green fishing net.

Jonathan Bachman of the United States, a photographer for Thomson Reuters, won the Contemporary Issues - Singles category with an image of Ieshia Evans being detained in Baton Rouge during a July 9 protest over the death of Alton Sterling, a black man killed by police. Evans stands bolt upright in a flowing dress as two police officers in body armor and helmets move to take her into custody.

Franklin called Bachman's image "an unforgettable sort of comment on passive resistance. It's really a lovely photograph. You'll never forget it."

AP photographer Vadim Ghirda, based in Romania, won second prize in the Contemporary Issues - Singles category with an emotionally charged photo of migrants crossing a river as they attempt to reach Macedonia from Greece.

Another AP photographer, Felipe Dana, came third in the Spot News - Singles category for his image of an explosion in Mosul, Iraq. And Santi Palacios won second in the General News - Singles category for a photo that ran on the AP wire of two Nigerian children who said their mother died on a rescue boat in the Mediterranean Sea of the coat of Libya.

For the first time, the World Press Photo awards for still images were announced at the same time as those for Digital Storytelling in the categories of Innovative Storytelling, Immersive Storytelling, Long Form and Short Form.

The digital award winners covered issues that included modern relationships, the rise of walls and fences around the world, and the story of an American boxer from Flint, Michigan. Among media whose work was recognized were The New York Times, The Washington Post and smaller independent producers.