With US-led efforts to end the war on hold and Washington's attention gripped by the conflict in the Middle East, European governments are keen to keep a spotlight on the continent's biggest land war in decades, now in its fifth year.
A group of 12 European foreign ministers, as well as numerous lower-ranking officials, arrived by train on Tuesday in Kyiv, where they were welcomed by Ukrainian Foreign Minister Andrii Sybiha, who noted the "grim anniversary" of the shocking atrocities in Bucha.
Russian troops quickly occupied the town after invading Ukraine on February 24, 2022.
They stayed for about a month. When Ukrainian troops retook Bucha they found more than 400 bodies left by Russia's cleansing operation.
"Such a strong European presence (in Ukraine) on this day demonstrates that justice for this and other Russian atrocities is inevitable," Sybiha said in a post on X.
"Comprehensive accountability for Russian crimes is vital to restore justice in Europe."
At the Church of Saint Andrew in Bucha, after viewing dozens of graphic photographs and a video display of the massacres with his EU counterparts, Polish Foreign Minister Radek Sikorski was grim.
"Anybody who claims that (Russian President) Vladimir Putin is not a war criminal should come and see for themselves," Sikorski told The Associated Press.
Authorities say many of the victims were gunned down in the street, and some had their hands tied behind their backs, and others showed signs of torture or rape.
The United Nations has documented more than 70 summary executions.
Part of Tuesday's meeting between the EU officials and their Ukrainian counterparts was to focus on reassuring Kyiv of continued European efforts to hold Russia to account for its invasion.
On the way to Kyiv, European Union foreign policy chief Kaja Kallas underlined the importance of ensuring that those who gave the orders to kill in places like Bucha are held to account, as much as those who carried the atrocities out.
"One of the things that is really necessary is accountability. Otherwise, you have revenge and retaliation," Kallas said.
"If you don't see people doing this to your family held accountable, you will want revenge."
The Iran war is a top priority for the United States and risks diverting resources that Kyiv needs, such as air defence systems, while providing Russia with windfall profits through high energy prices.
"We can't let it (the Ukraine war) slip off the table," Kallas said.
"We are the ones who have to keep this up because nobody else does."
US-mediated negotiations to end the war are going nowhere, and it's unclear when they might resume after being put on ice while the Middle East conflict unfolds.
The EU has faced its own challenges in helping Ukraine.
The bloc failed to approve new sanctions on Russia in February after surprise objections from Hungary.
Budapest has also blocked a 90 billion-euro ($A150 billion) loan to Ukraine as Kyiv runs low on cash.
Russia, meanwhile, hopes to reap a windfall from a surge in oil prices and a US temporary waiver on Russian oil sanctions designed to ease supply shortages.
In response, Ukraine has intensified its long-range drone attacks on Russian oil facilities, which have rattled Moscow.
Ukraine's defence ministry said its forces carried out a series of strikes in the past week targeting Russia's oil export infrastructure on the Baltic Sea, hitting key facilities in the Leningrad region used to ship crude and petroleum products.
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