Russia-Ukraine updates: US sanctions Russian military shipbuilder, diamond miner

Several world leaders on Sunday reacted to images shared by Ukraine's president's office, claiming to show the bodies of civilians scattered on the streets after the withdrawal of Russian troops from areas northwest of Kyiv.

In some of the photos, unarmed civilians appear to have been executed with their hands tied behind their backs.

NATO Secretary-General Jens Stoltenberg called the deaths of civilians in Bucha a “brutality" on CNN's "State of the Union" show, and said “I strongly welcome” an investigation by International Criminal Court, which has opened an investigation into war crimes in Ukraine.

"You can't but [see] those images as a punch to the gut ... Since the aggression, we've come out and said that we believe Russian forces have committed war crimes and we've been working to document that, to provide the information that we have to the relevant institutions and organizations that will put all of this together," U.S. Secretary of State Anthony Blinken told CNN's State of the Union Sunday.

"Russia’s despicable attacks against innocent civilians in Irpin and Bucha are yet more evidence that Putin and his army are committing war crimes in Ukraine," U.K. Prime Minister Boris Johnson said. "No denial or disinformation from the Kremlin can hide what we all know to be the truth -- Putin is desperate, his invasion is failing, and Ukraine’s resolve has never been stronger. I will do everything in my power to starve Putin’s war machine. We are stepping up our sanctions and military support, as well as bolstering our humanitarian support package to help those in need on the ground. The UK has been at the forefront of supporting the international Criminal Court's investigation into atrocities committed in Ukraine. The Justice Secretary has authorized additional financial support and the deployment of specialist investigators – we will not rest until justice is served," Johnson said.

Other world leaders expressed their feelings on social media.

"Appalled by reports of unspeakable horrors in areas from which Russia is withdrawing. An independent investigation is urgently needed. Perpetrators of war crimes will be held accountable," European Commission President Ursula von der Leyen posted on Twitter.

"Mass killings of Ukrainian civilians by #Russia are clear war crimes," Estonia's Prime Minister Kaja Kallas said on Twitter.. "We need courage, moral clarity and more action to stop it. Indifference is the mother of all crimes. Evidence must be gathered, saved for trials, and perpetrators must face justice. We need a 5th round of strong EU sanctions as soon as possible. Finally, our top priority should be increased military aid to #Ukraine. They need it to take back their cities and free people from Russian occupation and repression. #StandWithUkraine"

The prime minister of Slovenia, Janez Janša also weighed in on Twitter: "This are massive crimes against humanity. Russian army behaves as a horde of KGB executioners at Katyn. And at many other places after and before. Never bearing responsibility. After seeing #BuchaMassacre, we are terrified to even imagine what we will see in #Mariupol."

Belgium's Foreign Minister Sophie Wilmès, also posted om Twitter: "The images from the city of #Bucha confirm the fears we have had since February, which have led us to support several international investigations, including that of the @IntlCrimCourt. Impunity must not be allowed."

"Terrible images of destruction and reported executions of civilians in Bucha, Ukraine, in wake of Russian aggression. Reminiscent of darkest scenes from European history. To fight impunity :flag-se: will support @IntlCrimCourt investigation, incl financially and with seconded personnel," Sweden's prime minister, Magdalena Andersson, also posted to Twitter

-ABC News' Christine Theodorou

The Minister for Foreign Affairs of Ukraine, Dmytro Kuleba, called on the International Criminal Court and other international organizations to investigate Russians committing war crimes and crimes against humanity.

"I urge the International Criminal Court and international organizations to send their missions to Bucha and other liberated towns and villages of the Kyiv region, in cooperation with Ukrainian law enforcement agencies, to collect all evidence of Russian war crimes as carefully as possible," Kuleba said Sunday on Times UK radio.

"We are still collecting and looking for bodies, but the toll has already gone into the hundreds. Dead bodies lie on the streets. They killed civilians while in and out of these villages and towns," he said.

-ABC News' Yulia Drozd

Plumes of dark smoke rose on Sunday over Odessa, Ukraine, after an early morning Russian attack on the strategic and historic port city.

Missiles struck critical infrastructure facilities in the southern city, which sits on the Black Sea, Ukraine’s southern command announced. Casualties have not yet been reported.

According to the Ukrainian military, some Russian missiles were shot down by air defenses.

Missiles first hit Odessa on the opening night of Russia's invasion and again late last month. Residents have been bracing for Russia to launch an offensive to take the city.

Russia’s military on Sunday claimed the attack destroyed an oil refinery and three fuel depots, which had been supplying fuel to a nearby group of Ukrainian troops.

-ABC News’ Yulia Drozd

Ukrainian President Volodymyr Zelenskyy issued a new address Saturday updating the progress of the country's defense against Russian forces.

Ukrainian forces are regaining control of the Kyiv and Chernihiv regions, according to the president.

"There are more and more Ukrainian national flags in the areas that have been temporarily occupied," Zelenskyy said.

Zelenskyy, however, said his country hasn't received any new weapon systems from the West and chastised Western allies.

"Every Russian missile that hit our cities and every bomb dropped on our people, on our children, only adds black paint to the history that will describe everyone on whom the decision depended; [the] decision whether to help Ukraine with modern weapons," he said.

-ABC News' Jason Volack