Many countries had their worst showing in more than a decade in an index gauging public sector corruption, from the U.S. and France to authoritarian nations such as Russia and Venezuela.

Fighting corruption has been a goal for Ukraine's government ever since a 2014 revolution toppled a Russian-backed leader and fuelled Ukrainians' hope for a European future.

Spanish Prime Minister Pedro Sánchez has presented 15 anti-corruption measures and said he will not step down despite corruption scandals involving his Socialist Party.