Footage emerged of the Ukrainian prisoner smoking a cigarette in a trench and saying the words "Glory to Ukraine" before being shot.

The Ukrainian serviceman has been identified as Tymofiy Shadura who has been considered missing since the start of last month after hostilities in the Bakhmut area.

An investigation has been launched by Ukraine to find the killers of the soldier, with Ukrainian Foreign Minister Dmytro Kuleba saying the video was "another proof this war is genocidal."

Tributes have also been paid to the unarmed prisoner with several top Ukrainian athletes appearing in a video.

Kharlan and Bilosiuk, Olympic gold medallists in fencing and biathlon respectively, were among those to feature as each athlete said the words "Glory to the Heroes".

Tennis star Elina Svitolina, skeleton racer Vladyslav Heraskevych, biathlete Artem Pryma and karateka Stanislav Horuna also appeared in the video as well as a number of footballers including Mykhailo Mudryk, Taras Stepanenko and Yevhen Konoplyanka.

Ukrainian President Volodymyr Zelenskyy also spoke out against the killing of the soldier.

"A video appeared today showing how the occupants brutally killed a soldier who bravely said to their face: 'Glory to Ukraine'," said Zelenskyy.

"I want us all together, united to respond to his words: 'Glory to the hero, glory to heroes'.

"Glory to Ukraine will always be heard in Ukraine and millions will always respond 'Glory to heroes', always."