Photo: twitter

Wladimir Klitschko

Wladimir Klitschkois continuing to share testimony of the war occurring in his home country of Ukraine sinceVladimir Putin’s Russian invasionbegan there in February.

The former heavyweight champion of the world, 46, posted a harrowing video to his Twitter account on Sunday, from the city of Bucha in Ukraine. (Warning: this post contains graphic content.)

The clip shows Klitschko — who is also brother to Vitali Klitschko, the mayor of Ukrainian capital city Kyiv — speaking to the camera in front of an industrial site.

“What happened here, and everywhere in Ukraine, what is happening… This is not [a] special operation. This is not military [objects]. This is civilians,” Klitschko said, while showing two dead bodies that appear to be bound laying on the ground behind him.

“They’ve been shot in the head with tied hands behind their back. This is genocide of the Ukrainian population,” he continued. “And that’s exactly what Russian regime, Putin’s regime, Russian army is doing. Killing the civilians with tied hands behind their back and with a shot in their heads.”

For more on this story, listen below to our daily podcast on PEOPLE Every Day.

The grim video is just one piece of upsetting content Klitschko shared on his Twitter showing the brutality in Bucha, which is on the outskirts of Kyiv and hasseen many civilian deaths.

On Monday morning, hetweeted, “There are no words for these crimes. But there are those responsible for these crimes.”

RELATED VIDEO: Oksana Masters Donated Some of Her Prize Money to No Child Forgotten: “I Didn’t Have That…in Ukraine”

Never miss a story — sign up forPEOPLE’s free weekly newsletterto get the biggest news of the week delivered to your inbox every Friday.

Russia’sattack on Ukrainecontinues after their forces launched a large-scale invasion on Feb. 24 — the first major land conflict in Europe in decades.

With NATO forces massing in the region around Ukraine, various countries have also pledged aid or military support to the resistance. Ukrainian PresidentVolodymyr Zelenskyycalled for peace talks — so far unsuccessful — while urging his country to fight back.

Putin insists Ukraine has historic ties to Russia and he is acting in the best security interests of his country. Zelenskyy vowed not to bend.

“Nobody is going to break us, we’re strong, we’re Ukrainians,“he told the European Unionin a speech in the early days of the fighting, adding, “Life will win over death. And light will win over darkness.”

source: people.com