European leaders were set to meet in South Africa on Saturday to hash out alternatives to a US plan to halt Russia's war in Ukraine seen as favouring Moscow, nearly four years after it invaded its neighbour.

The 28-point blueprint to end the Kremlin's aggression sparked alarm in Kyiv and European capitals, with Ukrainian President Volodymyr Zelenskyy saying Friday that his country could face a stark choice between standing up for its sovereign rights and preserving the American support it needs.