The UK will “continue to pursue more options for bolstering Ukraine’s self-defence”, Prime Minister Boris Johnson said, as he commended the country’s people on their “fortitude” in the face of Russian aggression.

       In a call with Ukrainian president Volodymyr Zelensky on Sunday, Mr Johnson said the UK would “continue to stand behind Ukraine in all their efforts to bring an end to this disastrous conflict”.

       Meanwhile, the Department of Health and Social Care said 21 Ukrainian children will receive lifesaving cancer treatment in England after being brought over by the UK Government with the support of Polish authorities and clinicians.

       Mr Johnson commended Mr Zelensky and the Ukrainian people on their “fortitude”, adding that Russian president Vladimir Putin’s “barbaric actions” were “testing not just Ukraine but all of humanity”, No 10 said.

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       The men also “condemned the murders of Brent Renaud and countless innocent Ukrainians, and the abduction of the mayors of Dniprorudne and Melitopol”.

       It was reported on Sunday that Mr Renaud, an acclaimed US filmmaker, was killed after Russian forces opened fire on his vehicle near the Ukrainian capital Kyiv.

       Mr Zelensky has accused Russia of kidnapping the mayor of Melitopol, a port city in the south of Ukraine.

       And Ukrainian foreign minister Dmytro Kuleba tweeted on Sunday that “Russian war criminals” had “abducted another democratically elected Ukrainian mayor, head of Dniprorudne Yevhen Matveyev”.

       It came as 35 people were killed in an attack on a military training base in western Ukraine.

       Mr Johnson was said to have told Mr Zelensky during their call that the UK would “continue to pursue more options for bolstering Ukraine’s self-defence”.

       “The Prime Minister outlined the support the UK continues to deliver to Ukraine,” a No 10 spokesman said.

       “He said the UK would continue to pursue more options for bolstering Ukraine’s self-defence, working with partners including at Tuesday’s meeting of the Joint Expeditionary Force (JEF) in London.

       “The Prime Minister said the UK would continue to stand behind Ukraine in all their efforts to bring an end to this disastrous conflict.”

       The Ukrainian president tweeted on Sunday: “Held talks with (UK) PM @BorisJohnson and (Czech Republic) PM @P_Fiala. Talked about (Ukrainian) people’s struggle against Russian aggression, about Russia’s criminal attacks on civilians.

       The Prime Minister said the UK would continue to stand behind Ukraine in all their efforts to bring an end to this disastrous conflict

       No 10 spokesman

       “Thanked the partners for their important support. We appreciate it. #StopRussia”.

       Later, Foreign Secretary Liz Truss said she had spoken to her Ukrainian counterpart Mr Kuleba.

       She tweeted: “Good to speak to @DmytroKuleba. The bravery of the Ukrainian leadership and people is immense.

       “(The UK) is doing all we can to support including defensive weapons and humanitarian aid.”

       Mr Kuleba added that the pair had spoken about “next steps to apply more sanctions on Russia”.

       He tweeted: “Pressure must increase until Russia ceases its meaningless aggression and stops barbaric war crimes. Grateful to the UK for stepping up support for Ukraine.”

       Mr Johnson is preparing to embark on a series of meetings with Nordic and Baltic leaders this week as he seeks to bolster European resilience following Russia’s invasion of Ukraine.

       The Prime Minister will host a summit of the JEF in London, where he will urge leaders to work together to ensure no further nations fall victim to Vladimir Putin’s aggression, No 10 said.

       Earlier on Sunday, it was disclosed that more than 3,000 visas had been issued to Ukrainians seeking refuge in the UK, with “tens of thousands” potentially set to benefit from a new humanitarian scheme.

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       Levelling Up Secretary Michael Gove also announced that local authority areas would be entitled to more than ￡10,000 per Ukrainian refugee using the fresh route to the UK.

       “Additional payments” will be available to support school-age children who need to be accommodated within the education system, he said.