1 of 5 | Local residents stand next to a destroyed Russian tank, as Russia's attack on Ukraine continues, in Bucha, near Kyiv region, Ukraine on Sunday. Photo by Vladyslav Musienko/UPI | License Photo
April 3 (UPI) -- U.S. Secretary of State Antony Blinken said on Sunday that images of Ukrainian civilians alleged to have been executed in the city of Bucha are a "punch to the gut."
"Since the aggression, we've come out and said that we believe that Russian forces have committed war crimes," Blinken told CNN.
"We've been working to document that, to provide the information we have to the relevant instructions and organizations that will put all of this together. And there needs to be accountability for it."
Blinken will travel to Brussels, Belgium, on Monday for a meeting of foreign ministers of NATO member nations, the State Department said in a press release. He will also meet with foreign ministers of the Group of Seven nations.
Ursula von der Leyen, president of the European Commission, called for an investigation into Russia war crimes on Sunday after the revelations.
"Appalled by reports of unspeakable horrors in areas from which Russia is withdrawing. An independent investigation is urgently needed," von der Leyen said in a statement. "Perpetrators of war crimes will be held accountable."
Her comments came hours after Ukraine's Defense Ministry posted a video to social media accusing Russian forces of executing civilians in the Ukrainian city of Bucha. The video purports to show the bodies of at least three people in civilian clothing lining a street.
"The Ukrainian city of Bucha was in the hands of animals for several weeks," the Defense Ministry said. "Local civilians were being executed arbitrarily, some with hands tied behind their backs, their bodies scattered in the streets of the city."
In the post, the Defense Ministry also called the scenes from Bucha as a "New Srebrenica" in a reference to a massacre during the Bosnian War in which more than 8,000 people were killed in 1995.
Mykhailo Podolyak, a senior adviser to Ukrainian President Volodymyr Zelensky, shared graphic images to Twitter purporting to show the bodies of men and women shot dead with their hands tied behind their backs.
"These people were not in the military. They had no weapons. They posed no threat," Podolyak said. "How many more such cases are happening right now in the occupied territories?"
The Russian Defense Ministry denied killing civilians in a statement to Telegram on Sunday and called the video "fake."
"Given that the troops left the city on March 30, where were these footage for four days?" the Russian Defense Ministry said. "The bodies in the video seem to have been deliberately laid out in order to create a more dramatic picture."
The alleged executions of Ukrainians in Bucha came as Russian forces withdrew from the city, which sits on the west bank of the Dnipro River near Kyiv.
British Foreign Secretary Liz Truss said in a statement that she was "appalled by atrocities in Bucha and other towns in Ukraine."
"Reports of Russian forces targeting innocent civilians are abhorrent," she said. "The UK is working with others to collect evidence and support @IntlCrimCourt war crimes investigation. Those responsible will be held to account."
French President Emmanuel Macron called the images of the alleged executions "unbearable" in a statement posted to Twitter. Macron has been a major figure in attempting to negotiate peace between Russia and Ukraine.
"In the streets, hundreds of cowardly murdered civilians. My compassion for the victims, my solidarity with the Ukrainians," Macron said. "The Russian authorities will have to answer for these crimes."