US military volunteers fighting alongside Ukraine’s armed forces have branded President Donald Trump a “jackass” over his peace talks with Vladimir Putin, saying Ukraine’s future was not a “business deal”.

Hundreds of former US troops have fought on Kyiv’s side in the conflict over the last three years, following Ukraine’s President Volodymyr Zelensky’s creation of the International Legion at the start of the war.

Most have reacted furiously to the news last week of Mr Trump’s private phone call to Putin, in which he apparently ruled out Nato membership for Kyiv and conceded that Moscow could keep Ukrainian territory it has currently occupied.