One of the mechanisms Europe has at its disposal to make up the shortfall of American backing is to fully seize frozen Russian assets held in the region.

President Trump’s threat to abandon Ukraine added urgency to plans to fund security or reconstruction with the roughly $300 billion owned by Russia’s central bank.

On the eve of a major E.U. summit on defense and Ukraine, a group of Ukraine supporters and right activists gathered outside the European Council building on Wednesday, asking E.U. leaders to seize frozen Russian assets to fund Ukraine’s fight for survival.