About 20 countries are interested in joining a "coalition of the willing" to help Ukraine, according to UK officials.

It is not thought every one of the countries, which are largely from Europe and the Commonwealth, would necessarily send troops but some could provide other support.

The plan, spearheaded by the UK and France, was set out by Prime Minister Sir Keir Starmer at this weekend's summit of 18 European and Canadian leaders, and would work to uphold any ceasefire in Russia's war on Ukraine.

Russia's foreign minister Sergei Lavrov said such a move "can't be allowed" because it would amount to the "direct, official and unveiled involvement of Nato members in the war against Russia".

It comes as Kyiv attempts to mend relations with Washington after the US paused its military aid to Ukraine and intelligence sharing in a bid to bring President Zelensky to the negotiating table.

Speaking on a visit to a defence firm in Merseyside, Sir Keir said it would be a "big mistake" to think that "all we've got to do is wait for a deal now" between Ukraine and Russia, which US President Donald Trump claims to be attempting to broker.

The PM said it would be crucial that "if there is a deal - and we don't know there will be - that we defend the deal", which meant ensuring Ukraine was "in the strongest position".

But the PM stressed that defence plan should be made "in conjunction with the United States... it's that ability to work with the United States and our European partners that has kept the peace for 80 years now".

It is understood a meeting of officials was held on Tuesday to discuss providing security guarantees following any peace deal.

British officials said it was "early days" but welcomed what they described as the expressions of interest in joining a "coalition of the willing" as a "highly positive step".

The Prime Minister's Deputy Official Spokesman said the government had been "very clear that it is for Europe and for the UK to step up and I think you are seeing evidence of that consistently."

The UK and France have proposed a one-month truce "in the air, at sea and on energy infrastructure", backed up by a coalition of supportive western countries, but this has been rejected by Russia.

The UK announced a £1.6bn missile deal for Ukraine on Sunday and has now signed another deal with an Anglo-American security firm Anduril, to provide Ukraine with more advanced attack drones.

Also on Thursday, Defence Secretary John Healey held talks with his US counterpart Pete Hegseth in Washington DC.

At the meeting, Healey said the US had challenged Europe to step up on defence spending and the UK had responded.

"We have, we are and we will further," he said.

Hegseth said the UK was a "critical" partner, adding European leadership of the Nato alliance was "the future of defence on the continent".

Earlier, the Ministry of Defence (MoD) confirmed another security deal, worth nearly £30m and backed by the International Fund for Ukraine.

The deal will see Kyiv supplied with cutting-edge Altius 600m and Altius 700m systems - designed to monitor an area before striking targets that enter it - to help tackle Russian aggression in the Black Sea.

The announcement comes amid concerns that the US move to halt intelligence-sharing with Ukraine will affect the country's ability to use western weaponry and deprive it of advanced information about incoming threats.

In Brussels, the president of the European Commission, Ursula von der Leyen, held an emergency defence summit as the EU grapples with the prospect of Trump reducing security assistance for Europe.

Proposing an 800 billion euro (£670 billion) defence package, von der Leyen said this was a "watershed moment", adding: "Europe faces a clear and present danger and therefore Europe has to be able to protect itself, to defend itself, as we have to put Ukraine in a position to protect itself and to push for a lasting and just peace."

European Union leaders met Zelensky, who thanked them for their support, and said: "We are very thankful that we are not alone. These are not just words, we feel it."

Turkey indicated Thursday it could play a part in peacekeeping efforts, while Ireland's Prime Minister Micheal Martin said Irish troops could be involved in peacekeeping but would not be deployed in any "deterrent force".

Australian Prime Minister Anthony Albanese has also said he is "open" to sending troops to Ukraine as peacekeepers.

On Thursday Russia rejected calls for a temporary ceasefire in Ukraine, with foreign ministry spokeswoman Maria Zakharova telling reporters: "Firm agreements on a final settlement are needed. Without all that, some kind of respite is absolutely unacceptable."