Sir Keir Starmer and Emmanuel Macron will host a meeting of the coalition of the willing when the French President visits Britain next week.
The Prime Minister and France’s leader will dial into a meeting with allies on Thursday, as Mr Macron makes his first state visit to the UK, it is understood.
Britain and France have led efforts to establish the coalition, a peacekeeping force aimed at policing any future ceasefire deal in Ukraine, and deterring further threats by Russia.
The effectiveness of the coalition has been called into question, as only London and Paris have so far indicated they would provide frontline soldiers towards it.
The peacekeeping mission would also be predicated on American air support, something which US President Donald Trump has been unwilling to openly say he would provide.
Russia launched a massive barrage of drone strikes on Kyiv overnight, reportedly the largest since the war began.
Some 550 drones and missiles were fired at Ukraine in the strikes, with the capital Kyiv the primary target.
At least 23 people were injured, with 14 taken to hospital, according to the city’s mayor Vitali Klitschko.
The strikes came hours after Mr Trump held a phone call with Russian President Vladimir Putin, pushing him to accept a truce.
No 10 said the continued Russia strikes were “clear evidence that Putin was not serious about peace”, as it condemned them.
A Downing Street spokesman added: “Since Ukraine agreed to an unconditional ceasefire over four months ago, 700 civilians have been killed, more than 3,000 injured,
“We are, alongside our allies, absolutely united in support of a just and lasting peace in Ukraine. We are clear that must start with a full, immediate and unconditional ceasefire.”
The UK’s immediate focus is “stepping up our support Ukraine, ratcheting up the pressure on Russia”, he said.
Mr Trump has halted some shipments of critical weapons to Kyiv in recent days, including those used for air defences.
Ukraine has warned the move will prevent it from defending against Russian air strikes.
