Christopher Ford, secretary of the Ukraine Solidarity Campaign, said: "The millions who have stood by Ukraine are appalled at the conduct of Trump and threat of betrayal, promises made to do whatever it takes to help Ukraine win have collapsed without any explanation.
Mariia Pastukh, of Vsesvit Ukraine solidarity collective, said the location of the rally near the Russian embassy was to draw attention to "Russia's imperialist ambitions, which fuelled its brutal and unprovoked invasion of Ukraine".
She said: "We call for Russia to withdraw its troops from all of Ukraine, for Trump to end his backroom power games and for the UK to strengthen its leadership in safeguarding Ukraine's sovereignty and Europe's security.".
They added that they were calling for "renewed solidarity, that peace must come with the full withdrawal of Russian forces", as well as for a "surge in military aid to strengthen Ukraine in any negotiations and be able to finally end the occupation if no just agreement is secured".
In a joint statement, the organisers of Saturday's march said Ukraine has been made vulnerable by not being provided with enough aid to defeat Russia and is being "expected to consign its own citizens to occupation under a deal imposed by Trump".
