European leaders met in London to formulate a plan to help end the war in Ukraine. But even potential peacekeepers face political and economic hurdles.

Ukrainian President Volodymyr Zelensky has said it would need an international force of up to 200,000 troops to sustain a ceasefire along the 600 mile (960km) line of contact between the two opposing armies, Russia and Ukraine.

European leaders sought to assemble what Britain called a “coalition of the willing” to secure Ukraine after any US-brokered ceasefire, as they gathered in London to coordinate defense spending hikes amid concerns of an American pullback.