The United Kingdom said Friday the Kremlin was "fully responsible" for the death of a British captive in east Ukraine as rescue workers in Vinnytsia scoured debris for missing people after devastating Russian rocket attacks.
The comments from British Foreign Secretary Liz Truss came as Kyiv announced it had taken delivery of sophisticated rocket-launcher systems, part of a growing Western-supplied arsenal that Ukraine says is changing dynamics on the battlefield.
"I am shocked to hear reports of the death of British aid worker Paul Urey while in the custody of a Russian proxy in Ukraine," Truss said.
"Russia must bear the full responsibility for this," she said.
Rescue workers were still clearing debris throughout the day in the wake of devastating Russian strikes in the central Ukrainian city of Vinnytsia that killed nearly two dozen people, including three children.
Russia claimed the strikes -- hundreds of kilometres away from frontline fighting -- had killed Ukrainian military officials and foreign arms suppliers.
But among those killed was four-year-old Liza Dmitrieva, who had Down's syndrome and whose death spurred an outpouring after footage her final moments alive went viral on social media.
Ukrainian President Volodymyr Zelensky said in response that "no other country in the world poses the same kind of terrorist threat as Russia".
Eighteen people were unaccounted for and more than 70 were hospitalised, the presidency said. Some 400 people were involved in clean-up operations, the emergency services announced Friday.
- Outpouring for slain toddler -
The missile strikes on Vinnytsia are the latest attacks to carry a heavy civilian toll and come less than a week after strikes on Chasiv Yar in the Donetsk region left nearly 50 dead.
Officials initially believed four-year-old Liza's mother had been killed too, but announced Friday she was alive in a "critical" condition after surgery.
First Lady Olena Zelenska said early Friday she was "horrified" by Liza's death and images of her overturned pushchair released by local authorities.
Moscow said it had targeted Ukraine military officials meeting to discuss arms supplies and aircraft repairs with foreign representatives.
"As a result of the strike, the participants of the meeting were destroyed," the Russian defence ministry said.
But a senior US defence official rejected the claim, telling reporters: "I have no indication that there was a military target anywhere near that."
Moscow launched its invasion on February 24 and the conflict has killed thousands of people, destroyed cities and forced millions to flee their homes.
Ukraine has repeatedly urged allies to supply it with advanced, long-range precisions artillery systems that would allow it to target Russian forces deeper inside Ukrainian-held territory.
Defence Minister Oleksiy Reznikov said Friday Ukraine had taken delivery of a first batch of sophisticated M270 rocket systems, adding to a growing arsenal of Western-supplied artillery Kyiv says is changing dynamics on the battlefield.
"They will be good company for Himars on the battlefield," Oleksiy said, referring to US precision rocket systems recently deployed in the conflict.
The heaviest fighting recently in Ukraine has focused on the industrial Donbas region in the east, where a grinding trench war and artillery duels are morphing into a war of attrition.
- 'Clearing' Donbas town Siversk -
Moscow-backed separatists said Friday they were closing in on their next target, Siversk, after wresting control of sister cities Lysychansk and Severodonetsk two weeks ago.
And Donetsk separatist official Daniil Versonov said rebel fighters were "clearing" eastern districts of Siversk in small groups.
A strike Friday hit the central square in Kramatorsk, a major city and an administrative centre of the Donbas, where the town hall and cultural centre are located. Authorities said no one was hurt since it happened during the curfew.
Genya, a 72-year-old resident, described seeing from his balcony "something burning in the middle of the square then it exploded".
The pro-Moscow authorities also announced British citizen Urey had died in their captivity on July 10. They say he was a veteran of conflicts in Afghanistan and the Middle East.
Truss said however Urey "was in Ukraine to try and help the Ukrainian people in the face of the unprovoked Russian invasion," echoing claims from NGOs and a legion of foreign fighters backing Kyiv.
Negotiations to end the conflict collapsed early in the war but Russian and Ukrainian delegations met in Istanbul this week to discuss unblocking Ukraine's grain exports.
The countries at war are among the world's largest producers and the conflict has pushed up prices with Ukraine unable to export grain through its Black Sea ports.
A Russian military spokesman said Friday however an agreement to unblock grain exports from Ukrainian ports would be ready "soon".