Austrian Chancellor Karl Nehammer confirmed he plans to travel to Moscow on Monday and meet with Russian President Vladimir Putin.

Nehammer noted in a Twitter post on Sunday that while Austria is militarily neutral, the country's position on Russia's war against Ukraine is that it must stop.

Nehammer said that humanitarian corridors and a ceasefire need to be established and that a full investigation should take place appraising allegations of war crimes committed by Russia in Ukraine.

The chancellor said he has notified Ukrainian President Volodymyr Zelenskyy and his European partners of his plan to meet with Putin.

Nehammer's decision to meet with Putin comes after he visited Kyiv on Saturday and met with Zelenskyy.

-ABC News' Christine Theodorou

A top Ukrainian prosecutor said the bodies of more than 1,200 Ukrainians allegedly killed by Russian forces have been found in or near the capital of Kyiv since the start of the Russian invasion in February.

Ukraine's prosecutor-general, Iryna Venediktova. made the grim announcement on Sunday, the 46th day of the war in Ukraine.

"As of the morning of April 10, we found the bodies of 1,222 people who died during the Russian occupation of Kyiv region. This is only in Kyiv region," Venediktova said.

Venediktova said many of the bodies recovered in the Kyiv region are those of civilians.

"Of course, what we have seen on the ground in all regions of Ukraine are war crimes, crimes against humanity and we will do everything to prosecute them," Venediktova said.

In addition to the atrocities found near the capital city, Venediktova mention at rocket attack Friday on a train station in Kramatorsk in the Donetsk Oblast of eastern Ukraine that killed 50 people, including five children. Venediktova called the deadly attack in Kramatorsk a "war crime."

Pope Francis prayed for an Easter truce in Ukraine during Palm Sunday services at the Vatican, telling thousands gathered in St. Peter's Square that "nothing is impossible for God."

In his angelus prayer following Palm Sunday Mass, the pope expressed hope for a period of calm to allow leaders in the now 46-day war to negotiate peace.

"Let the weapons be put down! Let the Easter truce begin," Pope Francis said. "But not to provide more weapons and pick up the combat again – no! – a truce that will lead to peace, through real negotiation that is even disposed to some sacrifice for the good of the people. In fact, what victory is there in planting a flag on a pile of rubble?"

Vatican police estimated that about 65,000 people made the pilgrimage to St. Peter's Square for the start of Holy Week. It was the first Palm Sunday Mass celebrated in St. Peter's Square in two years due to the pandemic.

Many of those in attendance held palm branches in a symbolic gesture commemorating the return of Jesus to Jerusalem.

“When we resort to violence ... we lose sight of why we are in the world and even end up committing senseless acts of cruelty," Francis said during his homily. "We see this in the folly of war, where Christ is crucified yet another time."

Russian forces on Saturday night attacked cities throughout eastern Ukraine, with shelling near Mariupol and Kharkiv, Ukraine's General Staff of the Armed Forces said in a statement on Sunday.

Russian and Ukrainian forces clashed overnight near Izyum, near Kharkiv, in the Donetsk Oblast, as Russian troops attempted to "break through" the local defense, the statement said.

"The East of Ukraine is on fire again," Lesia Vasylenko, a government minister, said. "All news of the morning: troops amassing around Kharkiv, artillery attacks all across towns in Donetsk and Luhansk regions. The same geography as in 2014/15, just wider. Russian aggression continues."

Russian missiles fired during the night hit a military base near Zvonetskoe, west of Izyum, Russia's Armed Forces said in a Sunday morning update. Moscow claimed its missiles also had hit Chuhuev military airfield, near Kharkiv, destroying anti-aircraft missile launchers and systems.

Ukraine's military claimed to have repelled eight Russian attacks, destroying four tanks, since Saturday morning.

The U.K. Ministry of Defense on Saturday warned that Russia's attacks throughout the country carried high risks to civilians.

"Russian forces continue to use IEDs to inflict casualties, lower morale, and restrict Ukrainian freedom of movement," the ministry said. "Russian forces also continue to attack infrastructure targets with a high risk of collateral harm to civilians, including a nitrate acid tank at Rubizhne."

President Joe Biden on Thursday announced a new $800 million security assistance package to help Ukrainians fighting in the eastern Donbas region. This funding includes heavy artillery weapons, tactical drones and howitzers.

This package includes 72 new howitzers. Combined with the 18 howitzers announced last week, the 90 howitzers headed to Ukraine can equip five battalions, according to the administration.

Biden noted that he’s run out of pre-approved money and equipment to send to Ukraine and he appealed to Congress to approve more.

When pressed by ABC News on how long the U.S. can sustain this level of spending, Biden said, “We have the capacity to do this for a long time."

He went on, "The question is, are we going to continue to maintain the support of the international community? And keep the pressure on Putin to prevent him from overrunning the country, No. 1, and No. 2, make sure we continue to maintain the economic sanctions, which, over time, and we're beginning to see, they’re devastating their economy and their ability to move forward."

Biden also announced a separate $500 million in economic aid to Ukraine to help fund government operations like salaries, pensions and social programs.

The president added that the U.S. is now banning Russian-affiliated ships from American ports.

Biden met with Ukrainian Prime Minister Denys Shmyhal Thursday morning ahead of his remarks.

-ABC News' Luis Martinez and Sarah Kolinovsky