- Ukraine's top diplomat said the mass killings in Bucha are just the beginning of Russian "crimes."
- Dmytro Kuleba said the "horrors" of Mariupol and Bucha justify "serious" G7 and EU sanctions.
- Western leaders slammed Russia on Monday after the discovery of mass graves in the Kyiv suburb.
Ukraine's foreign minister said the discovery of mass civilian killings in the Kyiv suburb of Bucha are just the "tip of the iceberg."
"The horrors that we've seen in Bucha are just the tip of the iceberg of all the crimes that have been committed by Russian army in the territory of Ukraine so far," Dmytro Kuleba said during a Monday press conference with UK Foreign Secretary Liz Truss in Warsaw, Poland.
Hundreds of Ukrainian civilians were found last weekend buried in mass graves in Bucha, which up until a few days ago had been under Russian occupation for weeks.
Satellite images revealed partially excavated mass graves, while journalists and Ukrainian officials described corpses throughout the streets.
In the wake of the discovery, Western leaders and humanitarian organizations expressed outrage over the killings — with President Joe Biden calling for a war crimes trial against Russian President Vladimir Putin.
Truss, meanwhile, tweeted earlier on Monday that "reports of shallow graves outside Kyiv are truly horrifying."
"We are working with allies and the ICC to ensure the perpetrators are held to account," Truss said. "We will not rest until Russia has paid the price for these appalling crimes."
Kuleba also said during the press conference that the humanitarian situation in the besieged southern port city of Mariupol is "much worse compared to what we've seen in Bucha and other cities, and towns and villages, nearby Kyiv."
Mariupol has been the target of a brutal Russian shelling campaign for weeks, as attempts to evacuate civilians and establish humanitarian corridors have repeatedly failed or been blocked.
Russian forces have hit a school, maternity hospital, and even a theater marked as a shelter with children inside. It's still unclear exactly how many Ukrainian civilians have died in Mariupol since the February 24 Russian invasion.
Kuleba said the "horrors" of Mariupol and Bucha justify "serious" G7 and European Union sanctions, and slammed Western countries for continuing to buy Russian energy exports.
Lithuania's foreign minister delivered similar remarks on Sunday, urging European countries to avoid buying Russian oil or gas after the mass killings in Bucha were uncovered.
"Buying [Russian] oil&gas is financing war crimes. Dear EU friends, pull the plug. Don't be an accomplice," Gabrielius Landsbergis said.
After Monday's press conference, Kuleba said he coordinated with Truss to add further sanctions on Russia and weapons delivery to Ukraine.
"After Bucha massacre, Russia must be stopped now," he tweeted. "No more half-measures. G7 and EU sanctions must be devastating. Ukraine must receive all necessary weapons."