The award-winning Ukrainian writer Victoria Amelina has died from her injuries after a Russian missile hit a pizza restaurant in the eastern city of Kramatorsk on Tuesday.

The war crimes researcher becomes the 13th person to have died in the attack.

The writers' association PEN Ukraine said doctors "did everything they could to save her life, but unfortunately the wound was fatal".

Human rights activists have called the attack a war crime.

Kramatorsk is under Ukrainian control but is close to Russian-occupied parts of Ukraine.

Amelina, 37, was dining with a delegation of Colombian journalists and writers in the city's popular Ria Lounge when the missile hit. Around 60 others were injured in the attack.

She was rushed to hospital in Dnipro, but succumbed to her injuries on Friday, PEN Ukraine said.

"It is with great pain that we inform you that the heart of the writer Victoria Amelina stopped beating on 1 July," the group said in a statement.

"In the last days of Victoria's life, her family and friends were by her side."

Amelina was one of Ukraine's most celebrated young writers who started documenting war crimes after Russia's full-scale invasion last year. She also started working with children near the frontline.

Last year she unearthed the diary of children's writer Volodymyr Vakulenko, who was abducted and killed by Russian troops in the city of Izyum soon after the invasion.

Her first non-fiction book in English, War and Justice Diary: Looking at Women Looking at War, is due to be published.

In an earlier statement confirming that Amelina had been injured in the attack, PEN Ukraine and war crimes watchdog Truth Hounds said that members of both groups had travelled to the frontlines with Amelina.

"Now, Victoria has become a victim of a war crime herself," they said.

A post pinned to her Twitter profile shows Amelina taking a photo of a bombed building in Ukraine.

"It's me in this picture," the post reads.

"I'm a Ukrainian writer. I have portraits of great Ukrainian poets on my bag. I look like I should be taking pictures of books, art, and my little son. But I document Russia's war crimes and listen to the sound of shelling, not poems. Why?"