The toll from a devastating strike on the central Ukrainian city of Dnipro rose to 40 on Monday, as more bodies were pulled from the debris of one of Russia's deadliest attacks since its invasion.
Kyiv has called for more weapons to defend itself and at the weekend received pledges of British tanks, but Russian President Vladimir Putin warned more armaments would only intensify fighting and the Kremlin vowed to burn the gear.
In Dnipro, residents gathered to get warm drinks and food next to the partially collapsed Soviet-style residential building that was ripped open by the strike on Saturday.
The emergency services gave the new toll specifying that three children were among those dead, and that 29 people were still unaccounted for.
The Kremlin claimed its forces were not responsible and pointed to an unsubstantiated theory circulating on social media that Ukrainian air defence systems had caused the damage.
"The Russian armed forces do not strike residential buildings or social infrastructure. They strike military targets," Kremlin spokesman Dmitry Peskov told reporters.
EU presidency holder Sweden condemned "in the strongest terms" the attack, with Prime Minister Ulf Kristersson telling reporters that "intentional attacks against civilians are war crimes".
UN Secretary-General Antonio Guterres also condemned the attack, with his spokesperson saying it was "another example of a suspected violation of the laws of war."
'These tanks will burn'
To withstand Russian attacks, Ukraine has in recent weeks been pressing Western backers to supply its forces with advanced tanks, in particular the German-designed Leopard model.
Berlin has been heavily criticised over its stuttering response to the war in Ukraine.
After months of criticism - and a series of gaffes - German Defence Minister Christine Lambrecht resigned on Monday.
Lambrecht's move comes days before the Ukraine Defence Contact Group, which coordinates arms supplies to Kyiv, is due to meet at the Ramstein Air Base in Germany.
Britain this weekend pledged 14 Challenger 2 tanks to Ukraine, which would make it the first Western country to supply the heavy tanks Kyiv has been calling for.
Putin on Monday slammed Kyiv's "destructive" policies that "bet on the intensification of hostilities with the support of Western sponsors who are ramping up the supplies of weapons."
His spokesperson told reporters that "these tanks are burning and will burn."
A large team of Ukrainian ministers and officials headed by First Lady Olena Zelenska, meanwhile began a major effort at the World Economic Forum in the Swiss resort town of Davos to lobby for greater Western aid and weapons deliveries.
"That's why I'm here," Kyiv mayor and former heavyweight champion boxer Vitali Klitschko, told reporters when asked about the need for fresh help.
"That's why it's very important to talk directly... it's very important to have a personal connection."
'Prosecute Russian leaders'
Russia and its close ally Belarus have announced the beginning of new joint military drills.
Belarus had allowed Moscow's forces to launch their invasion from its territory last February.
Its defence ministry said the air force exercises would involve joint "tactical" flights and that every airfield in Belarus would be involved.
"The exercise is purely defensive in nature," Pavel Muraveyko, first deputy state secretary of Belarus's Security Council, said.
German Foreign Minister Annalena Baerbock meanwhile called for a special tribunal to prosecute Russian leaders, as Moscow faced war crimes accusations over the Dnipro attack.
"We need to voice a clear message to the Russian leadership here and now that a war of aggression will not go unpunished," Baerbock said.
Calls have grown for a way to try to punish Russian leaders for the crime of aggression, as the Hague-based International Criminal Court (ICC) cannot do so under its rules.
Germany's top diplomat said she had discussed with Ukraine and other allies a "special solution" that could "derive its jurisdiction from Ukrainian criminal law."
Ukrainian soldiers have arrived in the United States to learn how to use the Patriot air defence system, the Pentagon's most advanced air defence system.
Washington had promised Kyiv a Patriot battery in a significant victory for Ukraine which had been demanding them for a long time.
The Patriot missiles - which cost three million dollars each - can shoot down cruise missiles, short-range ballistic missiles and aircraft at a height significantly higher than the systems currently in place.