April 4, 2022 Russia-Ukraine news

Russian forces are "actively withdrawing" from the Sumy Oblast in northeastern Ukraine, according to the regional governor, and taking their equipment with them.

Last week saw an influx of Russian troops between Bilopillya and Konotop — located to the northwest of the city of Sumy — where they "were shooting indiscriminately and terrorizing the population," said Dmytro Zhyvytsky, head of the regional administration in the Sumy region, on his Telegram channel on Sunday.

Sumy region lies 30 miles (48 kilometers) from the border with Russia and was one of the first cities to have been attacked as part of the Russian invasion. 

The city of Sumy is where close to 1,700 students were forced to hide in their hostels as the invasion began.

International condemnations continued Sunday after shocking images emerged from the town of Bucha, just northwest of Kyiv, with Western leaders calling for war crimes investigations and increasing sanctions on Russia. United Nations Secretary-General António Guterres said an independent probe into the killings was "essential."

Here are the latest headlines from the war in Ukraine:

Mass graves and civilians "executed": Images from AFP on Saturday show the bodies of at least 20 men found strewn across a street in Bucha, which Ukrainian officials say had just been liberated from Russian forces. The Russian Ministry of Defense claimed the extensive footage was "fake." CNN reporters also observed a mass grave in the town, with Bucha's mayor saying that there could be up to 300 victims buried on site. Mayor Anatoliy Fedoruk told Reuters the civilians had been "executed."

Zelensky outrage: Ukrainian President Volodymyr Zelensky called for an end of Russian "war crimes" in a video address Sunday, and for Russian leaders to be held accountable for the military's actions. "I want all the leaders of the Russian Federation to see how their orders are being fulfilled." He earlier called the events in Bucha "genocide."

Hungary's Orban calls Zelensky an "opponent": Hungarian Prime Minister Viktor Orban said in his victory speech his re-election sends a message not only to the European Union, but also to Zelensky, who he named along with a host of other perceived grievances as "opponents." Orban is known as an ally of Russian President Vladimir Putin.

On the ground: The besieged city of Mariupol is still a hotbed for fighting and airstrikes and remains a "key objective of the Russian invasion," the UK's Ministry of Defense said in an intelligence report. The southern coastal city of Odesa came under attack Sunday, with a local official saying a Russian missile strike had hit "critical infrastructure." The northern city of Chernihiv is about 70% destroyed following an assault by Russian troops, the city’s mayor said. And the regional military governor of Kharkiv said Russian forces had fired on a district, causing civilian casualties.

Filmmaker killed: Lithuanian documentary filmmaker Mantas Kvedaravičius was killed in Mariupol, the Ukrainian Defense Ministry’s information agency reported Sunday on Twitter. His 2011 documentary “Barzakh” focused on Russia’s war in Chechnya and earned him the Amnesty International Film Prize.

Shocking images of carnage in the town of Bucha, near the Ukrainian capital Kyiv, show civilian bodies littering the street after five weeks of near-constant firefights. 

The photos were captured by Agence France-Presse on Saturday, the same day Ukraine declared the town liberated from Russian troops.

Here's what we know so far:

Lithuanian documentary filmmaker Mantas Kvedaravičius was killed in Mariupol, the Ukrainian Defense Ministry’s information agency reported Sunday on Twitter.

Mariupol has been the center of intense bombardment from Russian strikes in recent weeks.

Lithuanian President Gitanas Nausėda expressed his condolences in a statement.

“We have lost not only in Lithuania, but also in the world, a well-known creator, who until the last moment, despite the danger, worked in Ukraine, which was attacked by the aggressor Russia. I wish strength and strength to M. Kvedaravičius' relatives, friends and all fans of his talent, " Nausėda said.

Lana Estemirova, the daughter of Natalia Estemirova, a human rights investigator from Chechnya who was murdered in 2009, mourned the death of Kvedaravičius on Twitter.

“Mantas was a family friend, a frequent guest in our Grozny flat. A brave and kind soul. I can’t believe this,” Estemirova said.

“RIP dearest Mantas -- a true artist, cinema poet, mysterious and brave soul. A terrible loss for Lithuanian cinema community and all the world. Our hearts are broken,” Lithuanian documentary director Giedre Zickyte said on Facebook.

In 2016, Kvedaravičius‘ documentary “Mariupolis” premiered at the Berlin International Film Festival.

His 2011 documentary “Barzakh” focused on Russia’s war in Chechnya and earned him the Amnesty International Film Prize.

In a video address, Ukrainian President Volodymyr Zelensky called for an end to Russian “war crimes.”

His address came after reports of dozens of bodies found in the streets and mass graves in the Ukrainian city of Bucha.

Zelensky called on Russian leaders to be held accountable for the actions of the nation's military.

“I want all the leaders of the Russian Federation to see how their orders are being fulfilled. Such orders. Such a fulfillment. And joint responsibility. For these murders, for these tortures, for these arms torn off by explosions that lie on the streets. For shots in the back of the head of tied people. This is how the Russian state will now be perceived. This is your image,” Zelensky said.

In his address, Zelensky announced a “mechanism of justice” would be established to investigate crimes committed by Russian soldiers in Ukrainian territory. The mechanism would be supported by the Ministry of Foreign Affairs, the Office of the Prosecutor General, the National Police, the Security Service, the Intelligence Service and other government branches, he said.

“This mechanism will help Ukraine and the world bring to concrete justice those who unleashed or in any way participated in this terrible war against the Ukrainian people and in crimes against our people,” he said.

Zelensky said he will provide more information on the state of Ukrainian territory that was occupied by Russian forces.

He also noted efforts are underway to restore electricity and water to Bucha, as well as reestablishing medical institutions and infrastructure.

 Zelensky once again invoked the need for stronger sanctions against Russia.

“There will definitely be a new package of sanctions against Russia. But I'm sure that's not enough. More conclusions are needed. Not only about Russia, but also about the political behavior that actually allowed this evil to come to our land,” he said.

The top UN official said an "independent investigation" into the civilians killed in Bucha, Ukraine, is "essential" to ensure "effective accountability."

"I am deeply shocked by the images of civilians killed in Bucha, Ukraine," UN Secretary General António Guterres said in a statement Sunday.

"It is essential that an independent investigation leads to effective accountability," he continued.

A mass grave has been discovered in the town of Bucha, in the outskirts of the Ukrainian capital of Kyiv, a CNN team found. 

Bodies were first buried in the grave, on the grounds of the Church of St. Andrew and Pyervozvannoho All Saints, in the first days of the war, residents told CNN.

CNN saw at least a dozen bodies in body bags pilled inside the grave. Some were already partially covered. 

According to residents, more bodies are already buried on site. They said they belong mostly to civilians killed in the fighting around Bucha.

Residents told CNN that around 150 people are buried there. 

The mayor of Bucha said in public remarks on Saturday that there could be up to 300 victims buried on site.

CNN was unable to independently verify those numbers or the identities and nationalities of those buried in the grave.

The earth on the church grounds appeared to have been recently moved so it is feasible that a larger number of bodies is buried there. 

Bucha has seen some of the heaviest fighting since the war started. 

Destroyed Russian vehicles line the streets and most houses have been damaged in some way, with a large portion of the buildings there completely destroyed.

CNN's Senior International Correspondent Fred Pleitgen, producer Vasco Cotovio, producer Daria Markina and photojournalist Byron Blunt also saw people at the site of the mass grave crying and looking for the bodies of lost loved ones.

Listen to CNN's eyewitness account:

The northern Ukrainian city of Chernihiv is about 70% destroyed following an assault by Russian troops, Vladyslav Atroshenko, the city’s mayor, said Sunday.

The “consequences” of the attack by Russia in Chernihiv are “severe,” similar to the aftermath in other badly damaged cities and towns like Bucha, where bodies of civilians were found in the streets, as well as in Kharkiv and Mariupol, he said. 

The most urgent issues facing residents is a “concentration of Russian troops on the Belarusian border,” and concerns the city will be hit with more missiles and air bombs, Atroshenko added.

“Russians move around Ukraine like at home. And the fact that they left does not mean that they will not come back tomorrow. It takes about an hour and a half for them to get to us ... Today we can say it is quiet, there is cleaning, there is demining," he said.