The US has signalled that it could leave an international effort to prosecute Russia for invading Ukraine, The Telegraph can reveal.

US envoys refused to label Russia as an “aggressor” at a meeting of a “core group” of countries preparing a Nuremberg-style tribunal to try Vladimir Putin for his war crimes, according to Western officials.

Washington is similarly refusing to co-sponsor a United Nations statement that supports Ukraine’s territorial integrity and demands Moscow to withdraw its forces from the war-torn nation.

Mr Trump’s administration has also refused to sign off a planned G7 statement calling Russia the “aggressor” in the war with Ukraine to mark the third anniversary of the conflict on Monday.

The US president has blamed Ukraine for starting the war, branded Volodymyr Zelensky a “dictator” and pushed for Russia to be invited back to the alliance of industrialised nations.

European officials fear Mr Trump’s flattery of Putin could lead to the Russian despot being let off the hook for his invasion as part of any peace settlement.