Sir Keir Starmer will convene an emergency meeting at Downing Street on Sunday with key European leaders to address Ukraine's ongoing needs, Number 10 has confirmed.
The Prime Minister will welcome Ukrainian President Volodymyr Zelensky alongside French President Emmanuel Macron and German Chancellor Friedrich Merz for discussions on maintaining Western support.
The gathering comes amid escalating violence and follows Moscow's dismissal of Kyiv's overture for direct negotiations.
The summit will examine measures to apply additional pressure on Russia, according to sources.
The timing reflects a particularly turbulent period in the conflict, with military confrontations intensifying on multiple fronts over recent days.
Vladimir Putin has rebuffed President Zelensky's request for direct talks, describing the Ukrainian leader's Thursday letter as containing "some rather rude remarks".
The Russian president dismissed the possibility of a meeting during remarks at Russia's annual economic forum in St Petersburg on Friday.
When asked whether he would sit down with his Ukrainian counterpart, Mr Putin responded: "I don't see any point for now."
Keir Starmer is set to host the emergency meeting with Volodymyr Zelensky at No10 on Sunday
|PA
The Kremlin maintains that substantive negotiations between experts must occur before any leadership summit can take place.
Mr Putin restated his longstanding position that a ceasefire would merely allow Ukrainian forces to regroup.
"We need agreements - not for six months, not for three months, but for the long term," he said.
Ukrainian forces launched a significant drone assault on St Petersburg on Saturday, Russia's second-largest city, demonstrating Kyiv's expanding capacity to conduct operations deep within Russian territory.
LATEST DEVELOPMENTS:
Friedrich Merz is also set to attend the crunch talks
|PA
The attack on Saturday followed an earlier strike on the same city during the week, which President Zelensky had characterised in his letter to Mr Putin as "paying a visit".
Meanwhile, Russian forces continued their bombardment of Ukrainian territory overnight into Saturday.
Regional authorities in Dnipropetrovsk reported one fatality and three injuries as Moscow's military struck three districts approximately 30 times using drones and artillery, according to regional head Oleksandr Hanzha.
Earlier in the week, Russian attacks across Ukraine resulted in at least 13 deaths and 70 injuries, officials said.
The summit will examine measures to apply additional pressure on Russia, according to sources
|PA
Ukraine's capacity to conduct deep strikes within Russian borders has grown significantly since spring, with Kyiv deploying domestically manufactured long-range weaponry that provides increased operational independence.
Defence analysts view Moscow's intensified bombardment of Ukrainian cities, resulting in substantial civilian harm and infrastructure damage, as an effort to reclaim strategic momentum and demonstrate determination.
Former diplomat Tim Willasey-Wilsey has described the present phase as "a critical moment" in Russia's war on Ukraine.
Ukrainian forces reported hitting five vessels in the Sea of Azov on Friday that were allegedly transporting seized grain and military supplies, according to drone commander Robert Brovdi.
A Ukrainian drone accidentally detonated in Romania's Constanta port after Russian electronic warfare systems disrupted its navigation.